V4L/DVB (9569): uvcvideo: Sort the frame descriptors during parsing

The UVC specification does not require frame descriptors to be sorted by
bFrameIndex. At least one camera (145f:013e) is known not to sort the
descriptors properly, so they need to be sorted during parsing as the driver
then accesses them by index.

Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>