drm/amd/display: Clean up locking in dcn*_apply_ctx_for_surface()

[Why]

dcn*_disable_plane() doesn't unlock the pipe anymore, making the extra
lock unnecessary.

In addition - during full plane updates - all necessary pipes should be
locked/unlocked together when modifying hubp to avoid tearing in
pipesplit setups.

[How]

Remove redundant locks, and add function to lock all pipes. If an
interdependent pipe update is required, lock down all pipes. Otherwise,
lock only the top pipe for the updated pipe tree.

Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>