drm/amd/display: update dio for two pixel per container case

[why]
Processing rate of the DP encoder, must be programmed to be the same as
DIG_FIFO_OUTPUT_ PROCESSING_MODE in DP mode
0: 1 pixel per cycle
1: 2 pixel per cycle
Reviewed-by: Alvin Lee <Alvin.Lee2@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_dio_stream_encoder.c

@@ -286,6 +286,7 @@ static void enc32_stream_encoder_dp_unblank(
 		uint32_t n_vid = 0x8000;
 		uint32_t m_vid;
 		uint32_t n_multiply = 0;
+		uint32_t pix_per_cycle = 0;
 		uint64_t m_vid_l = n_vid;
 
 		/* YCbCr 4:2:0 : Computed VID_M will be 2X the input rate */
@@ -320,6 +321,10 @@ static void enc32_stream_encoder_dp_unblank(
 		REG_UPDATE_2(DP_VID_TIMING,
 				DP_VID_M_N_GEN_EN, 1,
 				DP_VID_N_MUL, n_multiply);
+
+		REG_UPDATE(DP_PIXEL_FORMAT,
+				DP_PIXEL_PER_CYCLE_PROCESSING_MODE,
+				pix_per_cycle);
 	}
 
 	/* make sure stream is disabled before resetting steer fifo */