[media] gscpa_ov519: Fix the bandwidth calc for enabling compression

Somehow the code has ended up assuming 1400 packets/sec which of course
is wrong for usb1 devices like the ov511 cameras. usb1 only does 1000
(isoc) packets / sec.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>