Convert CONFIG_OVERWRITE_ETHADDR_ONCE to Kconfig

This converts the following to Kconfig:
   CONFIG_OVERWRITE_ETHADDR_ONCE

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/README b/README
index 9e26278..3ebee1c 100644
--- a/README
+++ b/README
@@ -1071,13 +1071,6 @@
 		completely disabled. Anybody can change or delete
 		these parameters.
 
-		Alternatively, if you define _both_ an ethaddr in the
-		default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
-		Ethernet address is installed in the environment,
-		which can be changed exactly ONCE by the user. [The
-		serial# is unaffected by this, i. e. it remains
-		read-only.]
-
 		The same can be accomplished in a more flexible way
 		for any variable by configuring the type of access
 		to allow for those variables in the ".flags" variable
diff --git a/configs/M5253DEMO_defconfig b/configs/M5253DEMO_defconfig
index 4de6290..ea07997 100644
--- a/configs/M5253DEMO_defconfig
+++ b/configs/M5253DEMO_defconfig
@@ -25,6 +25,7 @@
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_FAT=y
 CONFIG_MAC_PARTITION=y
+CONFIG_OVERWRITE_ETHADDR_ONCE=y
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_USE_HOSTNAME=y
 CONFIG_HOSTNAME="M5253DEMO"
diff --git a/configs/M5275EVB_defconfig b/configs/M5275EVB_defconfig
index 01961e5..d84d9d9 100644
--- a/configs/M5275EVB_defconfig
+++ b/configs/M5275EVB_defconfig
@@ -31,6 +31,7 @@
 CONFIG_MII_INIT=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_CACHE=y
+CONFIG_OVERWRITE_ETHADDR_ONCE=y
 CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_SYS_FAULT_ECHO_LINK_DOWN=y
 CONFIG_SYS_RX_ETH_BUFFER=8
diff --git a/configs/eb_cpu5282_defconfig b/configs/eb_cpu5282_defconfig
index a831c1c..7304b49 100644
--- a/configs/eb_cpu5282_defconfig
+++ b/configs/eb_cpu5282_defconfig
@@ -32,6 +32,7 @@
 CONFIG_CMD_MII=y
 CONFIG_MII_INIT=y
 CONFIG_CMD_DATE=y
+CONFIG_OVERWRITE_ETHADDR_ONCE=y
 CONFIG_SYS_FAULT_ECHO_LINK_DOWN=y
 CONFIG_SYS_RX_ETH_BUFFER=8
 CONFIG_SYS_I2C_LEGACY=y
diff --git a/configs/eb_cpu5282_internal_defconfig b/configs/eb_cpu5282_internal_defconfig
index 6a673c9..5ecdda4 100644
--- a/configs/eb_cpu5282_internal_defconfig
+++ b/configs/eb_cpu5282_internal_defconfig
@@ -30,6 +30,7 @@
 CONFIG_CMD_MII=y
 CONFIG_MII_INIT=y
 CONFIG_CMD_DATE=y
+CONFIG_OVERWRITE_ETHADDR_ONCE=y
 CONFIG_SYS_FAULT_ECHO_LINK_DOWN=y
 CONFIG_SYS_RX_ETH_BUFFER=8
 CONFIG_SYS_I2C_LEGACY=y
diff --git a/env/Kconfig b/env/Kconfig
index c28d9e8..7ca992a 100644
--- a/env/Kconfig
+++ b/env/Kconfig
@@ -30,6 +30,15 @@
 	  Use this to permit overriding of certain environmental variables
 	  like Ethernet and Serial
 
+config OVERWRITE_ETHADDR_ONCE
+	bool "Enable overwriting ethaddr environment variables once"
+	depends on !ENV_OVERWRITE
+	help
+	  Enable this to allow for the ethaddr environment variables to be
+	  overwritten one time per boot, only. This allows for a default
+	  to be installed in the environment, which can be changed exactly ONCE
+	  by the user.
+
 config ENV_MIN_ENTRIES
 	int "Minimum number of entries in the environment hashtable"
 	default 64
diff --git a/include/configs/M5253DEMO.h b/include/configs/M5253DEMO.h
index 65a7aa0..bc156df 100644
--- a/include/configs/M5253DEMO.h
+++ b/include/configs/M5253DEMO.h
@@ -20,8 +20,6 @@
 	env/embedded.o(.text*);
 
 #ifdef CONFIG_DRIVER_DM9000
-#	define CONFIG_OVERWRITE_ETHADDR_ONCE
-
 #	define CONFIG_EXTRA_ENV_SETTINGS		\
 		"netdev=eth0\0"				\
 		"inpclk=" __stringify(CONFIG_SYS_INPUT_CLKSRC) "\0"	\
diff --git a/include/configs/M5275EVB.h b/include/configs/M5275EVB.h
index ff9f853..41974cf 100644
--- a/include/configs/M5275EVB.h
+++ b/include/configs/M5275EVB.h
@@ -38,10 +38,6 @@
 #define CFG_SYS_I2C_PINMUX_CLR	(0xFFF0)
 #define CFG_SYS_I2C_PINMUX_SET	(0x000F)
 
-#ifdef CONFIG_MCFFEC
-#	define CONFIG_OVERWRITE_ETHADDR_ONCE
-#endif				/* FEC_ENET */
-
 #define CONFIG_EXTRA_ENV_SETTINGS		\
 	"netdev=eth0\0"				\
 	"loadaddr=10000\0"			\
diff --git a/include/configs/eb_cpu5282.h b/include/configs/eb_cpu5282.h
index b267b74..26e4ade 100644
--- a/include/configs/eb_cpu5282.h
+++ b/include/configs/eb_cpu5282.h
@@ -42,10 +42,6 @@
  * Network								*
  *----------------------------------------------------------------------*/
 
-#ifdef CONFIG_MCFFEC
-#define CONFIG_OVERWRITE_ETHADDR_ONCE
-#endif
-
 /*-------------------------------------------------------------------------
  * Low Level Configuration Settings
  * (address mappings, register initial values, etc.)