ALSA: wss: Fix sparse warning wrt PCM format type

The PCM format type is with __bitwise, and it can't be converted from
integer implicitly.  Instead of an ugly cast, declare the function
argument of snd_wss_get_format() with the proper snd_pcm_format_t
type.

This fixes the sparse warnings like:
  sound/isa/wss/wss_lib.c:551:14: warning: restricted snd_pcm_format_t degrades to integer
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/isa/wss/wss_lib.c

@@ -541,7 +541,7 @@ static unsigned char snd_wss_get_rate(unsigned int rate)
 }
 
 static unsigned char snd_wss_get_format(struct snd_wss *chip,
-					int format,
+					snd_pcm_format_t format,
 					int channels)
 {
 	unsigned char rformat;