[media] it913x: fix correct endpoint size when pid filter on

I kept the count as the hardware default with dvb-usb-v2, with 5, users
can still run in to trouble with Video PIDs.
I have traced it to an incorrect endpoint size when the PID filter
is enabled. It also affected USB 2.0 with the filter on.

Reported-by: Antti Palosaari <crope@iki.fi>
Tested-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>