drm/amd/display: Enable 3 plane MPO

[why and how]
3 plane MPO is a new feature missing in a few resource files
Enable 3 plane MPO by setting slave planes to 2
Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Hansen Dsouza <Hansen.Dsouza@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/dcn315/dcn315_resource.c

@@ -1762,9 +1762,9 @@ static bool dcn315_resource_construct(
 	dc->caps.max_cursor_size = 256;
 	dc->caps.min_horizontal_blanking_period = 80;
 	dc->caps.dmdata_alloc_size = 2048;
-	dc->caps.max_slave_planes = 1;
-	dc->caps.max_slave_yuv_planes = 1;
-	dc->caps.max_slave_rgb_planes = 1;
+	dc->caps.max_slave_planes = 2;
+	dc->caps.max_slave_yuv_planes = 2;
+	dc->caps.max_slave_rgb_planes = 2;
 	dc->caps.post_blend_color_processing = true;
 	dc->caps.force_dp_tps4_for_cp2520 = true;
 	dc->caps.dp_hpo = true;

drivers/gpu/drm/amd/display/dc/dcn316/dcn316_resource.c

@@ -1764,9 +1764,9 @@ static bool dcn316_resource_construct(
 	dc->caps.max_cursor_size = 256;
 	dc->caps.min_horizontal_blanking_period = 80;
 	dc->caps.dmdata_alloc_size = 2048;
-	dc->caps.max_slave_planes = 1;
-	dc->caps.max_slave_yuv_planes = 1;
-	dc->caps.max_slave_rgb_planes = 1;
+	dc->caps.max_slave_planes = 2;
+	dc->caps.max_slave_yuv_planes = 2;
+	dc->caps.max_slave_rgb_planes = 2;
 	dc->caps.post_blend_color_processing = true;
 	dc->caps.force_dp_tps4_for_cp2520 = true;
 	dc->caps.dp_hpo = true;