drm/amdgpu/vcn: adjust unified queue code format

Fixed some errors and warnings found by checkpatch.pl.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Ruijing Dong <ruijing.dong@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>