drm/amd/display: On DCN1, Wait for vupdate on cursor updates

drm/amd/display: On DCN1, Wait for vupdate on cursor updates

[Why]
Cursor updates must acquire the pipe control lock to
prevent vupdate from triggering in the middle of cursor
programming. On DCN1 the pipe control lock prevents
pageflips from occurring. This means that a cursor update
right before vupdate can delay a pending pageflip

[How]
If the time until the next vupdate is less than a
conservative estimate of the cursor programming time,
wait until the vupdate has passed before locking.

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