ALSA: aloop: Fix PCM format assignment

ALSA: aloop: Fix PCM format assignment

Fix sparse warnings about PCM format assignment regarding the strong
typed snd_pcm_format_t:
  sound/drivers/aloop.c:352:45: warning: restricted snd_pcm_format_t degrades to integer
  sound/drivers/aloop.c:355:39: warning: incorrect type in assignment (different base types)
  sound/drivers/aloop.c:355:39:    expected unsigned int format
  sound/drivers/aloop.c:355:39:    got restricted snd_pcm_format_t [usertype] format
  sound/drivers/aloop.c:1435:34: warning: incorrect type in assignment (different base types)
  sound/drivers/aloop.c:1435:34:    expected long max
  sound/drivers/aloop.c:1435:34:    got restricted snd_pcm_format_t [usertype]
  sound/drivers/aloop.c:1565:39: warning: incorrect type in assignment (different base types)
  sound/drivers/aloop.c:1565:39:    expected unsigned int format
  sound/drivers/aloop.c:1565:39:    got restricted snd_pcm_format_t [usertype]

Some code in this driver assigns an integer value to snd_pcm_format_t
via control API, and they need to be with the explicit cast.

No functional changes, just sparse warning fixes.

Link: https://lore.kernel.org/r/20200206163945.6797-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>