ALSA: riptide: Fix PCM format type conversion

The PCM format type is with __bitwise, hence it needs to be explicitly
declared as snd_pcm_format_t, as warned by sparse:
  sound/pci/riptide/riptide.c:1028:34: warning: incorrect type in argument 1 (different base types)
  sound/pci/riptide/riptide.c:1028:34:    expected restricted snd_pcm_format_t [usertype] format
  sound/pci/riptide/riptide.c:1028:34:    got unsigned char [unsigned] format

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

sound/pci/riptide/riptide.c

@@ -1017,7 +1017,7 @@ getsamplerate(struct cmdif *cif, unsigned char *intdec, unsigned int *rate)
 static int
 setsampleformat(struct cmdif *cif,
 		unsigned char mixer, unsigned char id,
-		unsigned char channels, unsigned char format)
+		unsigned char channels, snd_pcm_format_t format)
 {
 	unsigned char w, ch, sig, order;