Hi all,

This patch fixes 3 inconsistencies between the pixfmt's returned by set_fmt
(through try_fmt / and try_fmt) and get_fmt.

* set_fmt (try_fmt) didn't set the pixformat field member
* get_fmt didn't take compression into account when setting sizeimage
* set_fmt (try_fmt) did take compression into account when setting sizeimage,
   but didn't add 600 to sizeimage for the jpeg header, as frame_alloc does

The later 2 are fixed by moving all buffer size calculations to
gspca_get_buff_size and using that everywhere for consistency.

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>

Regards,

Hans