Reduce buffer size of Interupt urb to 128 bytes and polling
interval to 8.

The devices buffer appears to only handle a maxium of 40 bytes.
If the buffer is full a slowing effect is noticed causing occasionnal
dropped streaming packets.
Signed-off-by: NMalcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>