drm/amd/display: Remove 4:2:2 DSC support

[why]
If DSC is available, a higher picture quality is achieved by using
DSC with 4:4:4 format. Using 4:2:2 instead does not offer any benefit
and would only introduce loss of quality. Removing it reduces
maintenance and testing effort.
Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_dsc.c

@@ -118,8 +118,8 @@ static void dsc2_get_enc_caps(struct dsc_enc_caps *dsc_enc_caps, int pixel_clock
 
 	dsc_enc_caps->color_formats.bits.RGB = 1;
 	dsc_enc_caps->color_formats.bits.YCBCR_444 = 1;
-	dsc_enc_caps->color_formats.bits.YCBCR_SIMPLE_422 = 1;
-	dsc_enc_caps->color_formats.bits.YCBCR_NATIVE_422 = 1;
+	dsc_enc_caps->color_formats.bits.YCBCR_SIMPLE_422 = 0;
+	dsc_enc_caps->color_formats.bits.YCBCR_NATIVE_422 = 0;
 	dsc_enc_caps->color_formats.bits.YCBCR_NATIVE_420 = 1;
 
 	dsc_enc_caps->color_depth.bits.COLOR_DEPTH_8_BPC = 1;