bcache: code cleanup in __bch_bucket_alloc_set()

In __bch_bucket_alloc_set() the lines after lable 'err:' indeed do
nothing useful after multiple cache devices are removed from bcache
code. This cleanup patch drops the useless code to save a bit CPU
cycles.
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20240528120914.28705-4-colyli@suse.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/alloc.c

@@ -498,8 +498,8 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
 
 	ca = c->cache;
 	b = bch_bucket_alloc(ca, reserve, wait);
-	if (b == -1)
-		goto err;
+	if (b < 0)
+		return -1;
 
 	k->ptr[0] = MAKE_PTR(ca->buckets[b].gen,
 			     bucket_to_sector(c, b),
@@ -508,10 +508,6 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
 	SET_KEY_PTRS(k, 1);
 
 	return 0;
-err:
-	bch_bucket_free(c, k);
-	bkey_put(c, k);
-	return -1;
 }
 
 int bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,