[MTD] Make init_mbx function static

The function init_mbx can become static, because it is not used
outside the file drivers/mtd/maps/mbx860.c. This patch adds the
needed keyword.
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.fi>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/maps/mbx860.c

@@ -55,7 +55,7 @@ struct map_info mbx_map = {
 	.bankwidth = 4,
 };
 
-int __init init_mbx(void)
+static int __init init_mbx(void)
 {
 	printk(KERN_NOTICE "Motorola MBX flash device: 0x%x at 0x%x\n", WINDOW_SIZE*4, WINDOW_ADDR);
 	mbx_map.virt = ioremap(WINDOW_ADDR, WINDOW_SIZE * 4);