drm/amd/display: Don't spam debug log on long reg waits

Certain reg waits take up to a frame. Don't spam the log when this
happens.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Jordan Lazare <Jordan.Lazare@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>