As currently implemented the default color matching descriptor is
appended after _all_ the formats and frames that the gadget is
configured with. According to the UVC specifications however this
is supposed to be on a per-format basis (section 3.9.2.6):

"Only one instance is allowed for a given format and if present,
the Color Matching descriptor shall be placed following the Video
and Still Image Frame descriptors for that format."

Associate the default color matching descriptor with struct
uvcg_format and copy it once-per-format instead of once only.
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Link: https://lore.kernel.org/r/20230202114142.300858-4-dan.scally@ideasonboard.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>