include: armv7: Enable distroboot across all configs

Since K3 devices are moving towards distroboot, remove duplicates and
add it in common file to import from.

Signed-off-by: Manorit Chawdhry <m-chawdhry@ti.com>
[trini: Add am65x_evm to this patch]
Signed-off-by: Tom Rini <trini@konsulko.com>