do_mounts: initrd_load() is never called w/o CONFIG_BLK_DEV_INITRD

When CONFIG_BLK_DEV_INITRD is not set, mount_initrd will always be
0, so initrd_load() won't be called. However, we need a stub to make
the compiler happy.

init/do_mounts.c

@@ -687,14 +687,16 @@ static void __init handle_initrd(void)
 #endif
 }
 
+#ifdef CONFIG_BLK_DEV_INITRD
 static int __init initrd_load(void)
 {
-#ifdef CONFIG_BLK_DEV_INITRD
 	create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, 0), NULL);
 	create_dev("/dev/initrd", MKDEV(RAMDISK_MAJOR, INITRD_MINOR), NULL);
-#endif
 	return rd_load_image("/dev/initrd");
 }
+#else
+static inline int initrd_load(void) { return 0; }
+#endif
 
 /*
  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.