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/intel8x0.c b/sound/pci/intel8x0.c
index 67f9e8b..2c5484e 100644
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -26,7 +26,7 @@
  *
  */      
 
-#include <asm/io.h>
+#include <linux/io.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>