drm/amd/display: Remove unused parameter plane_states

[Why]
The function dc_commit_updates_for_stream had a parameter called
plane_states.  It was never used.  It was getting in the way
of some cleanup work

[How]
Remove it

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>