m68k/amiga: Mark z_dev_present() __init

It's called from amiga_init_devices() only, which is __init.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/amiga/platform.c

@@ -57,7 +57,7 @@ static int __init amiga_init_bus(void)
 subsys_initcall(amiga_init_bus);
 
 
-static int z_dev_present(zorro_id id)
+static int __init z_dev_present(zorro_id id)
 {
 	unsigned int i;