ALSA: pcm: Add snd_mask_set_format() helper for standard usages

Many drivers calling snd_mask_set() need to do ugly cast with __force
for shutting up the sparse warnings.  Actually almost all of them are
about setting the format, so it's far better to provide a common
helper snd_mask_set_format() to pass SNDRV_PCM_FORMAT_* directly
without the cast.

There are a few other calls of snd_mask_set(), but they are in the PCM
core code, so we leave them for now.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>