board: AM43xx: fit: add support for selecting dtb dynamically

FIT allows for a multiple dtb in a single image. SPL needs a way to
detect the right dtb to be used. Adding support for the same.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
1 file changed