Convert CONFIG_LPC32XX_ETH to Kconfig

This converts the following to Kconfig:
   CONFIG_LPC32XX_ETH

Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index d63c0a9..a6171a7 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -423,6 +423,11 @@
 	  This driver implements a DSA switch driver for the KSZ9477 family
 	  of GbE switches using the I2C interface.
 
+config LPC32XX_ETH
+	bool "LPC32xx Ethernet MAC interface driver"
+	depends on ARCH_LPC32XX
+	default y
+
 config MVGBE
 	bool "Marvell Orion5x/Kirkwood network interface support"
 	depends on ARCH_KIRKWOOD || ARCH_ORION5X
diff --git a/include/configs/devkit3250.h b/include/configs/devkit3250.h
index 84098e7..bc5282a 100644
--- a/include/configs/devkit3250.h
+++ b/include/configs/devkit3250.h
@@ -30,11 +30,6 @@
  */
 
 /*
- * Ethernet
- */
-#define CONFIG_LPC32XX_ETH
-
-/*
  * NOR Flash
  */
 #define CONFIG_SYS_MAX_FLASH_SECT	71
diff --git a/include/configs/work_92105.h b/include/configs/work_92105.h
index 373af03..3324537 100644
--- a/include/configs/work_92105.h
+++ b/include/configs/work_92105.h
@@ -22,13 +22,6 @@
 #define CONFIG_SYS_INIT_SP_ADDR		(CONFIG_SYS_SDRAM_BASE + SZ_512K \
 					 - GENERATED_GBL_DATA_SIZE)
 
-/*
- * Ethernet Driver
- */
-
-#define CONFIG_LPC32XX_ETH
-/* FIXME: remove "Waiting for PHY auto negotiation to complete..." message */
-
 #define CONFIG_RTC_DS1374
 
 /*