minigbm: rockchip: Add support for buffers required by new camera subsystem

minigbm: rockchip: Add support for buffers required by new camera subsystem

It's much the same as what we did for i915 in:
d30c0a5 (minigbm: i915: Add support for buffers required by new camera subsystem)
https://chromium-review.googlesource.com/559315

BUG=b:65390035
TEST=test arc_camera3_test on scarlet, no more this error:
[0905/104926:ERROR:camera3_test_gralloc.cc (76)] Can't detect flexible YUV 420 format

Change-Id: Ib99687ff2aaaca0233fa950abbe8581bc3572b74
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-on: https://chromium-review.googlesource.com/670888
Reviewed-by: Tomasz Figa <tfiga@chromium.org>