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/als4000.c b/sound/pci/als4000.c
index 9460852..a3dea46 100644
--- a/sound/pci/als4000.c
+++ b/sound/pci/als4000.c
@@ -65,7 +65,7 @@
  * - power management? (card can do voice wakeup according to datasheet!!)
  */
 
-#include <asm/io.h>
+#include <linux/io.h>
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/gameport.h>