omap3: Define common SPL text base in Kconfig instead of defconfigs

The SPL text base was defined to the same value in each OMAP3 board
defconfig. Move the common definition to the Kconfig option
declaration instead.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Tested-by: Adam Ford <aford173@gmail.com> #am3517-evm
Reviewed-by: Tom Rini <trini@konsulko.com>
Tested-by: Derald D. Woods <woods.technical@gmail.com>
10 files changed