drm/amd/display: Allow truncation to 10 bits

The truncation isn't being programmed if the truncation
depth is set to 2, it causes an issue with dce11.2 asic
using 6bit eDP panel. It required to truncate 12:10 in order to
perform spatial dither 10:6.

This change will allow 12:10 truncation to be enabled.

Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -128,8 +128,7 @@ static void set_truncation(
 		return;
 	}
 	/* on other format-to do */
-	if (params->flags.TRUNCATE_ENABLED == 0 ||
-			params->flags.TRUNCATE_DEPTH == 2)
+	if (params->flags.TRUNCATE_ENABLED == 0)
 		return;
 	/*Set truncation depth and Enable truncation*/
 	REG_UPDATE_3(FMT_BIT_DEPTH_CONTROL,
@@ -144,7 +143,7 @@ static void set_truncation(
 /**
  *	set_spatial_dither
  *	1) set spatial dithering mode: pattern of seed
- *	2) set spatical dithering depth: 0 for 18bpp or 1 for 24bpp
+ *	2) set spatial dithering depth: 0 for 18bpp or 1 for 24bpp
  *	3) set random seed
  *	4) set random mode
  *		lfsr is reset every frame or not reset