Staging: xgifb: Fixed header file.

As suggested by checkpatch.pl, <linux/io.h> should be used instead of
<asm/io.h>.
Signed-off-by: Daniel Kenji Toyama <kenji.toyama@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/xgifb/vb_util.c

@@ -3,7 +3,7 @@
 #include "vb_struct.h"
 
 #include "XGIfb.h"
-#include <asm/io.h>
+#include <linux/io.h>
 #include <linux/types.h>
 
 #include "vb_util.h"