malta: Use I/O accessors for SuperI/O controller

Rather than passing the I/O port base address to the Super I/O code,
switch it to using outb such that it makes use of the I/O port base
address automatically.

Drop the extern keyword to satisfy checkpatch whilst here.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
diff --git a/board/imgtec/malta/superio.c b/board/imgtec/malta/superio.c
index eaa14df..7865ae2 100644
--- a/board/imgtec/malta/superio.c
+++ b/board/imgtec/malta/superio.c
@@ -45,19 +45,19 @@
 	{ SIOCONF_ACTIVATE,	0x01 },
 };
 
-void malta_superio_init(void *io_base)
+void malta_superio_init(void)
 {
 	unsigned i;
 
 	/* enter config state */
-	writeb(SIOCONF_ENTER_SETUP, io_base + SIO_CONF_PORT);
+	outb(SIOCONF_ENTER_SETUP, SIO_CONF_PORT);
 
 	/* configure peripherals */
 	for (i = 0; i < ARRAY_SIZE(sio_config); i++) {
-		writeb(sio_config[i].key, io_base + SIO_CONF_PORT);
-		writeb(sio_config[i].data, io_base + SIO_DATA_PORT);
+		outb(sio_config[i].key, SIO_CONF_PORT);
+		outb(sio_config[i].data, SIO_DATA_PORT);
 	}
 
 	/* exit config state */
-	writeb(SIOCONF_EXIT_SETUP, io_base + SIO_CONF_PORT);
+	outb(SIOCONF_EXIT_SETUP, SIO_CONF_PORT);
 }