V4L/DVB (9475): cx18: Disable write retries for registers that always change - part 1.

cx18: Disable write retries for registers that always change - part 1.
Interrupt related registers will likely not read back the value we just wrote.
Disable retries for these registers for now to avoid accidently discarding
interrupts.  More intelligent read back verification criteria are needed for
these and other registers (e.g. GPIO line registers), which will be addressed in
subsequent changes.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>