V4L/DVB (13214): tda18271: allow for i2c buses that cant send 16 bytes at once

There is already an option for sending 16 byte chunks rather that writing
39 bytes all at once during the tuner's initialization.  Some i2c buses
can't send 16 bytes at once, so create an option for sending 8 byte chunks.

Signed-off-by: Michael Krufky <mkrufky@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>