usb: device_next: uvc: fix frame interval sorting

The qsort() function takes a callback argument that is having the
same semantics as strcmp(). Fix uvc_compare_frmival_desc() sorting
to make qsort() list frame intervals in increasing values.

Fix a bug where Windows would not enumerate devices when the video device
have multiple frame interval supported.

Signed-off-by: Josuah Demangeon <me@josuah.net>