[Why]
NV12 has lower min dcfclk

[How]
Add update in update_bounding_box
Signed-off-by: NAlvin Lee <alvin.lee2@amd.com>
Reviewed-by: NJun Lei <Jun.Lei@amd.com>
Acked-by: NLeo Li <sunpeng.li@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>