[media] MFD: WL1273 FM Radio: MFD driver for the FM radio

This is the core of the WL1273 FM radio driver, it connects
the two child modules. The two child drivers are
drivers/media/radio/radio-wl1273.c and sound/soc/codecs/wl1273.c.

The radio-wl1273 driver implements the V4L2 interface and communicates
with the device. The ALSA codec offers digital audio, without it only
analog audio is available.

Signed-off-by: Matti J. Aaltonen <matti.j.aaltonen@nokia.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>