dts: Allow OF_LIST to depend on FIT_EMBED

OF_LIST will be useable by SPL and U-boot. Therefore, update its
dependency to allow it to be enable by either SPL or U-boot specific
config option.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-by: Andrew F. Davis <afd@ti.com>