sys/v4l2/: When probing the formats and sizes a camera supports, make sure the best ones (highest resolution, prefere...

Original commit message from CVS:
* sys/v4l2/gstv4l2src.c:
* sys/v4l2/v4l2src_calls.c:
When probing the formats and sizes a camera supports, make
sure the best ones (highest resolution, prefered format)
end up at the beginning of the probed caps and the less
desirable ones at the end.  This is important because the
order within the caps matters for things like fixation and
negotiation, ie. what format is chosen in the end.
With recent kernels, the current probing code will end up
querying the supported sizes from lowest resolution to
highest resolution, adding them to the probed caps in that
order, resulting to v4l2src fixating to the lowest possible
resolution if downstream does not express a size preference.
Also make up a somewhat random ranking of prefered output
formats for the same reason. Fixes #485828.