Convert CONFIG_CMD_EEPROM et al to Kconfig

This converts the following to Kconfig:
   CONFIG_CMD_EEPROM
   CONFIG_CMD_EEPROM_LAYOUT
   CONFIG_EEPROM_LAYOUT_HELP_STRING

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
[trini: Rework Kconfig logic slightly, define EEPROM location on TI eval
platforms]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/km_kirkwood_128m16_defconfig b/configs/km_kirkwood_128m16_defconfig
index 49080a8..0884688 100644
--- a/configs/km_kirkwood_128m16_defconfig
+++ b/configs/km_kirkwood_128m16_defconfig
@@ -12,6 +12,7 @@
 # CONFIG_CMD_IMLS is not set
 CONFIG_CMD_ASKENV=y
 CONFIG_CMD_GREPENV=y
+CONFIG_CMD_EEPROM=y
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_SF=y
 CONFIG_CMD_I2C=y