drm/exynos: mixer: enable NV12MT support for the video plane

The video processor supports a tiled version of the NV12 format,
known as NV12MT in V4L2 terms. The support was removed in commit
083500baefd5f4c215a5a93aef2492c1aa775828 due to not being a real
pixel format, but rather NV12 with a special memory layout.

With the introduction of FB modifiers, we can now properly support
this format again.

Tested with a hacked up modetest from libdrm's test suite on
an ODROID-X2 (Exynos4412).

Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
index cbd949a..f9a06b8 100644
--- a/drivers/gpu/drm/exynos/exynos_mixer.c
+++ b/drivers/gpu/drm/exynos/exynos_mixer.c
@@ -148,7 +148,8 @@ static const struct exynos_drm_plane_config plane_configs[MIXER_WIN_NR] = {
 		.pixel_formats = vp_formats,
 		.num_pixel_formats = ARRAY_SIZE(vp_formats),
 		.capabilities = EXYNOS_DRM_PLANE_CAP_SCALE |
-				EXYNOS_DRM_PLANE_CAP_ZPOS,
+				EXYNOS_DRM_PLANE_CAP_ZPOS |
+				EXYNOS_DRM_PLANE_CAP_TILE,
 	},
 };
 
@@ -500,6 +501,9 @@ static void vp_video_buffer(struct mixer_context *ctx,
 		return;
 	}
 
+	if (fb->modifier == DRM_FORMAT_MOD_SAMSUNG_64_32_TILE)
+		tiled_mode = true;
+
 	luma_addr[0] = exynos_drm_fb_dma_addr(fb, 0);
 	chroma_addr[0] = exynos_drm_fb_dma_addr(fb, 1);