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.