media: sun6i-csi: fix colorspace in sun6i_video_try_fmt()

With gstreamer 1.19.3 all attempts to capture video in YUV formats on
our Allwinner H3-based custom board with an ov5640 sensor result in
pipeline crashes with the following messages:

	Device '/dev/video0' does not support 2:0:0:0 colorimetry
	Additional debug info:
	Device wants 2:0:0:0 colorimetry

Fix this by setting the correct colorspace in sun6i_video_try_fmt().

Signed-off-by: Mikhail Rudenko <mike.rudenko@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>