[media] v4l: add Mediatek compressed video block format

Add V4L2_PIX_FMT_MT21C format used on MT8173 driver.
It is compressed format and need MT8173 MDP driver to transfer to other
standard format.

Signed-off-by: Tiffany Lin <tiffany.lin@mediatek.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index a4b5d36..39e19b4 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1249,6 +1249,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 		case V4L2_PIX_FMT_JPGL:		descr = "JPEG Lite"; break;
 		case V4L2_PIX_FMT_SE401:	descr = "GSPCA SE401"; break;
 		case V4L2_PIX_FMT_S5C_UYVY_JPG:	descr = "S5C73MX interleaved UYVY/JPEG"; break;
+		case V4L2_PIX_FMT_MT21C:	descr = "Mediatek Compressed Format"; break;
 		default:
 			WARN(1, "Unknown pixelformat 0x%08x\n", fmt->pixelformat);
 			if (fmt->description[0])