ALSA: Include linux/io.h instead of asm/io.h

Nowadays it's recommended.  Replace all in a shot.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/via82xx_modem.c b/sound/pci/via82xx_modem.c
index 884f49e..99b9137 100644
--- a/sound/pci/via82xx_modem.c
+++ b/sound/pci/via82xx_modem.c
@@ -31,7 +31,7 @@
  *      modems.
  */
 
-#include <asm/io.h>
+#include <linux/io.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>