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/board/ti/common/Kconfig b/board/ti/common/Kconfig
index 08c39d9..1187cf5 100644
--- a/board/ti/common/Kconfig
+++ b/board/ti/common/Kconfig
@@ -20,6 +20,7 @@
 	imply CMD_BOOTZ
 	imply CMD_DFU if USB_GADGET_DOWNLOAD
 	imply CMD_DHCP
+	imply CMD_EEPROM
 	imply CMD_EXT2
 	imply CMD_EXT4
 	imply CMD_EXT4_WRITE