media: amphion: correct the unspecified color space

in the E.2.1 of Rec. ITU-T H.264 (06/2019),
0 of colour primaries is reserved, and 2 is unspecified.
driver can map V4L2_COLORSPACE_LAST to 0,
and map V4L2_COLORSPACE_DEFAULT to 2.

v4l2_xfer_func and v4l2_ycbcr_encoding are similar case.

Fixes: 3cd08451 ("media: amphion: add vpu v4l2 m2m support")
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>