drivers: dio: Use <linux/io.h> instead <asm/io.h>

This patch fixes the checkpatch.pl warning:

< WARNING: Use #include <linux/io.h> instead of <asm/io.h>
< #36: FILE: drivers/dio/dio.c:36:
< +#include <asm/io.h>                             /* readb() */
Signed-off-by: Aleksa Vučković <aleksav013@gmail.com>
Link: https://lore.kernel.org/r/20220127135054.27281-1-aleksav013@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/dio/dio.c

@@ -33,7 +33,7 @@
 #include <linux/dio.h>
 #include <linux/slab.h>                         /* kmalloc() */
 #include <linux/uaccess.h>
-#include <asm/io.h>                             /* readb() */
+#include <linux/io.h>                           /* readb() */
 
 struct dio_bus dio_bus = {
 	.resources = {