drm/amd/display: Optimize amdgpu_dm_atomic_commit_tail()

[WHY]
The first two loops of for_each_oldnew_connector_in_state() both operate
on an HDCP queue.  If one isn't setup then each connector is iterated but
skipped TWICE.  This is wasteful for the majority of cases.

[HOW]
Combine the two HDCP related loops of for_each_oldnew_connector_in_state()
and check for the HDCP workqueue before even running either of them. This
should avoid running the functions in most cases, and if HDCP is setup only
run once.

Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>