ALSA: ad1816a: 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_ad1816a_get_format() with the proper snd_pcm_format_t
type.

This fixes the sparse warning like:
  sound/isa/ad1816a/ad1816a_lib.c:93:14: warning: restricted snd_pcm_format_t degrades to integer
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/ad1816a/ad1816a_lib.c

@@ -85,7 +85,8 @@ static void snd_ad1816a_write_mask(struct snd_ad1816a *chip, unsigned char reg,
 
 
 static unsigned char snd_ad1816a_get_format(struct snd_ad1816a *chip,
-					    unsigned int format, int channels)
+					    snd_pcm_format_t format,
+					    int channels)
 {
 	unsigned char retval = AD1816A_FMT_LINEAR_8;