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>

sound/ppc/tumbler.c

@@ -32,8 +32,8 @@
 #include <linux/interrupt.h>
 #include <linux/string.h>
 #include <linux/of_irq.h>
+#include <linux/io.h>
 #include <sound/core.h>
-#include <asm/io.h>
 #include <asm/irq.h>
 #include <asm/machdep.h>
 #include <asm/pmac_feature.h>