media: imx: add 16-bit grayscale support

Since commit 50b0f0aee839 ("gpu: ipu-csi: add 10/12-bit grayscale
support to mbus_code_to_bus_cfg") the IPU CSI can be configured to
capture 10-bit and 12-bit grayscale formats, expanded to 16-bit
grayscale, in bayer/generic data mode.
This patch adds support for V4L2_PIX_FMT_Y16 captured from sensors
that provide MEDIA_BUS_FMT_Y10_1X10 or MEDIA_BUS_FMT_Y12_1X12 data.

Cc: Jan Luebbe <jlu@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/staging/media/imx/imx-media-csi.c

@@ -409,6 +409,7 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
 	case V4L2_PIX_FMT_SGBRG16:
 	case V4L2_PIX_FMT_SGRBG16:
 	case V4L2_PIX_FMT_SRGGB16:
+	case V4L2_PIX_FMT_Y16:
 		burst_size = 4;
 		passthrough = true;
 		passthrough_bits = 16;

drivers/staging/media/imx/imx-media-utils.c

@@ -168,6 +168,15 @@ static const struct imx_media_pixfmt rgb_formats[] = {
 		.cs     = IPUV3_COLORSPACE_RGB,
 		.bpp    = 8,
 		.bayer  = true,
+	}, {
+		.fourcc = V4L2_PIX_FMT_Y16,
+		.codes = {
+			MEDIA_BUS_FMT_Y10_1X10,
+			MEDIA_BUS_FMT_Y12_1X12,
+		},
+		.cs     = IPUV3_COLORSPACE_RGB,
+		.bpp    = 16,
+		.bayer  = true,
 	},
 	/***
 	 * non-mbus RGB formats start here. NOTE! when adding non-mbus