drm/amd/display: Program CW5 for tracebuffer for dcn20

[Why]
On dcn21 this is programmed for tracebuffer support but isn't being
programmed on dcn20.

DMCUB execution hits an undefined address 65000000 on tracebuffer
access.

[How]
Program CW5.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dmub/src/dmub_dcn20.c

@@ -99,6 +99,13 @@ void dmub_dcn20_setup_windows(struct dmub_srv *dmub,
 	REG_SET_2(DMCUB_REGION4_TOP_ADDRESS, 0, DMCUB_REGION4_TOP_ADDRESS,
 		  cw4->region.top - cw4->region.base - 1, DMCUB_REGION4_ENABLE,
 		  1);
+
+	REG_WRITE(DMCUB_REGION3_CW5_OFFSET, cw5->offset.u.low_part);
+	REG_WRITE(DMCUB_REGION3_CW5_OFFSET_HIGH, cw5->offset.u.high_part);
+	REG_WRITE(DMCUB_REGION3_CW5_BASE_ADDRESS, cw5->region.base);
+	REG_SET_2(DMCUB_REGION3_CW5_TOP_ADDRESS, 0,
+		  DMCUB_REGION3_CW5_TOP_ADDRESS, cw5->region.top,
+		  DMCUB_REGION3_CW5_ENABLE, 1);
 }
 
 void dmub_dcn20_setup_mailbox(struct dmub_srv *dmub,