V4L/DVB (3639): Reduce FWSEND due to certain I2C bus adapter limits

The FWSEND parameter controls the size of the firmware chunks sent
down the I2C bus to the chip.  Previously this had been set to 1024
but unfortunately some I2C implementations can't transfer data in such
big gulps.  Specifically, the pvrusb2 driver has a hard limit of
around 60 bytes, due to the encapsulation there of I2C traffic into
USB messages.  So we have to significantly reduce this parameter.
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>