media: imx: utils: Default colorspace to SRGB

The function imx_media_init_mbus_fmt() initializes the imx subdevice
mbus colorimetry to some sane defaults when the subdevice is registered.
Currently it guesses at a colorspace based on the passed mbus pixel
format. If the format is RGB, it chooses colorspace V4L2_COLORSPACE_SRGB,
and if the format is YUV, it chooses V4L2_COLORSPACE_SMPTE170M.

While that might be a good guess, it's not necessarily true that a RGB
pixel format encoding uses a SRGB colorspace, or that a YUV encoding
uses a SMPTE170M colorspace. Instead of making this dubious guess,
just default the colorspace to SRGB.
Reported-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

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

@@ -388,8 +388,7 @@ int imx_media_init_mbus_fmt(struct v4l2_mbus_framefmt *mbus,
 
 	mbus->code = code;
 
-	mbus->colorspace = (lcc->cs == IPUV3_COLORSPACE_RGB) ?
-		V4L2_COLORSPACE_SRGB : V4L2_COLORSPACE_SMPTE170M;
+	mbus->colorspace = V4L2_COLORSPACE_SRGB;
 	mbus->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(mbus->colorspace);
 	mbus->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(mbus->colorspace);
 	mbus->quantization =