drm/amd/display: Allow spatial dither to 10 bpc on all DCE

Spatial dithering to 10 bpc depth was disabled for all DCE's.

Testing on DCE-8.3 and DCE-11.2 did not show any obvious ill
effects, but a measureable precision improvement (via colorimeter)
when displaying a fp16 framebuffer to a 10 bpc DP or HDMI connected
HDR-10 monitor.

v2: enable it for all DCEs (Alex)

Signed-off-by: Mario Kleiner <[e-mail]>
Cc: Alex Deucher <[e-mail]>
Reviewed-by: Mario Kleiner <[e-mail]> (v2)
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/dce/dce_opp.c

···
 	REG_UPDATE(FMT_BIT_DEPTH_CONTROL,
 		FMT_TEMPORAL_DITHER_EN, 0);
 
-	/* no 10bpc on DCE11*/
-	if (params->flags.SPATIAL_DITHER_ENABLED == 0 ||
-		params->flags.SPATIAL_DITHER_DEPTH == 2)
+	if (params->flags.SPATIAL_DITHER_ENABLED == 0)
 		return;
 
 	/* only use FRAME_COUNTER_MAX if frameRandom == 1*/