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.h b/board/imgtec/malta/superio.h
index 1450da5..271c462 100644
--- a/board/imgtec/malta/superio.h
+++ b/board/imgtec/malta/superio.h
@@ -10,6 +10,6 @@
 #ifndef __BOARD_MALTA_SUPERIO_H__
 #define __BOARD_MALTA_SUPERIO_H__
 
-extern void malta_superio_init(void *io_base);
+void malta_superio_init(void);
 
 #endif /* __BOARD_MALTA_SUPERIO_H__ */