[ALSA] fm801 - Add mute support for FM-only card with FM801 PCI to tuner bridge

This is improvement of the early support of the FM-only cards where the
fm801 chip represents the PCI to tuner bridge.
The tuner initialization isn't included the mute on as well as mute support
via V4L request. Proposed patch should fix this at least for 64-PCR model.

Signed-off-by: Andy Shevchenko <andy@smile.org.ua>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>