drm/amd/display: wait for test pattern after when all pipes are programmed

[why]
Currently we wait for test pattern after each pipe is programmed.  For
ODM combined scenario it will cause test pattern is shown on only half
screen for 1 frame. This is not desirable.

[how]
No wait between odm pipe programming, only wait after all pipes are
programmed.

Signed-off-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>