drm/amdgpu: Clean up errors in uvd_v7_0.c

Fix the following errors reported by checkpatch:

ERROR: spaces required around that ':' (ctx:VxE)
that open brace { should be on the previous line

Signed-off-by: Ran Sun <sunran001@208suo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>