rockpi4: capsule: Enable UEFI capsule update on RockPi4 boards

Enable the UEFI capsule update functionality on the RockPi4B and
RockPi4C boards. Support is being enabled for updating the idbloader
and u-boot firmware images residing on GPT partitioned uSD card
storage device.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>