ALSA: rme*: Use snd_pcm_format_t

Fix sparse warnings below by using snd_pcm_format_t properly:
   sound/pci/rme32.c:682:60: sparse: incorrect type in argument 2 (different base types)
  sound/pci/rme96.c:1006:69: sparse: incorrect type in argument 2 (different base types)
   .....

Signed-off-by: Takashi Iwai <tiwai@suse.de>