[media] gspca - ov519: Change the ovfx2 bulk transfer size

The 'normal' bulk transfer size did not work for 800x600.
By git commit c42cedbb, this 'normal' size was used for 1600x1200 only.
It will now be used back again for all resolutions but 800x600.

Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>