V4L/DVB: af901x: inform NXP TDA18218 tuner as know but not supported

There is no driver for new NXP TDA18218	tuner which is used by few recent
af9015 designs. af9015 uses number 179 as ID for that tuner. Inform this
tuner is not supported when device using that tuner is meet.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>