ALSA: au88x0: 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 vortex_alsafmt_aspfmt() with the proper snd_pcm_format_t
type.

This fixes the sparse warning like:
  sound/pci/au88x0/au88x0_core.c:2778:14: warning: restricted snd_pcm_format_t degrades to integer
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/au88x0/au88x0.h

@@ -241,7 +241,7 @@ static int vortex_core_init(vortex_t * card);
 static int vortex_core_shutdown(vortex_t * card);
 static void vortex_enable_int(vortex_t * card);
 static irqreturn_t vortex_interrupt(int irq, void *dev_id);
-static int vortex_alsafmt_aspfmt(int alsafmt, vortex_t *v);
+static int vortex_alsafmt_aspfmt(snd_pcm_format_t alsafmt, vortex_t *v);
 
 /* Connection  stuff. */
 static void vortex_connect_default(vortex_t * vortex, int en);

sound/pci/au88x0/au88x0_core.c

@@ -2770,7 +2770,7 @@ static int vortex_core_shutdown(vortex_t * vortex)
 
 /* Alsa support. */
 
-static int vortex_alsafmt_aspfmt(int alsafmt, vortex_t *v)
+static int vortex_alsafmt_aspfmt(snd_pcm_format_t alsafmt, vortex_t *v)
 {
 	int fmt;