Convert CONFIG_SPI to Kconfig

This converts the following to Kconfig:
   CONFIG_SPI

This partly involves updating code that assumes that CONFIG_SPI implies
things that are specific to the MPC8xx SPI driver.  For now, just update
the CONFIG tests.  This also involves reworking the default for
CONFIG_SYS_DEF_EEPROM_ADDR so that we don't set it when we cannot make a
reasonable default, as it does not cause any compile failures.

Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
index 3621dfa..1a6ed21 100644
--- a/arch/arm/mach-at91/Kconfig
+++ b/arch/arm/mach-at91/Kconfig
@@ -88,6 +88,7 @@
 	select DM_SPI
 	select DM_GPIO
 	select DM_ETH
+	select SPI
 
 config TARGET_AT91SAM9261EK
 	bool "Atmel at91sam9261 reference board"
@@ -202,6 +203,7 @@
 	select SUPPORT_SPL
 	select DM
 	select DM_SPI
+	select SPI
 
 config TARGET_MEESC
 	bool "Support meesc"
@@ -225,6 +227,7 @@
 	select DM_SPI
 	select DM_GPIO
 	select DM_ETH
+	select SPI
 
 config TARGET_SMARTWEB
 	bool "Support smartweb"
@@ -241,6 +244,7 @@
 	select SUPPORT_SPL
 	select DM
 	select DM_SPI
+	select SPI
 
 config TARGET_WB45N
 	bool "Support Laird WB45N"