[Why]
In cases where number of pipes available is less
than num_opp, there will opp instances that are
null
[How]
Add null check to skip over these opp instances
Fixes: 40de8403b998 ("drm/amd/display: Update OPP counter from new interface") Reviewed-by: Alvin Lee <alvin.lee2@amd.com> Acked-by: Roman Li <roman.li@amd.com> Signed-off-by: Samson Tam <samson.tam@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>