maple: fix wrong return value of maple_bus_init().

If KMEM_CACHE or maple_alloc_dev failed, the maple_bus_init() will return 0
rather than error, because the retval is not changed after KMEM_CACHE or
maple_alloc_dev failed.

Fixes: 17be2d2b1c33 ("sh: Add maple bus support for the SEGA Dreamcast.")
Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Lu Wei <[e-mail]>
Acked-by: John Paul Adrian Glaubitz <[e-mail]>
Signed-off-by: Rich Felker <[e-mail]>

drivers/sh/maple/maple.c

···
 
 	maple_queue_cache = KMEM_CACHE(maple_buffer, SLAB_HWCACHE_ALIGN);
 
-	if (!maple_queue_cache)
+	if (!maple_queue_cache) {
+		retval = -ENOMEM;
 		goto cleanup_bothirqs;
+	}
 
 	INIT_LIST_HEAD(&maple_waitq);
 	INIT_LIST_HEAD(&maple_sentq);
···
 		if (!mdev[i]) {
 			while (i-- > 0)
 				maple_free_dev(mdev[i]);
+			retval = -ENOMEM;
 			goto cleanup_cache;
 		}
 		baseunits[i] = mdev[i];