bcachefs: Fix shrinker names

Shrinkers are now exported to debugfs, so the names can't have slashes
in them.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_cache.c

@@ -476,7 +476,7 @@ int bch2_fs_btree_cache_init(struct bch_fs *c)
 	bc->shrink.count_objects	= bch2_btree_cache_count;
 	bc->shrink.scan_objects		= bch2_btree_cache_scan;
 	bc->shrink.seeks		= 4;
-	ret = register_shrinker(&bc->shrink, "%s/btree_cache", c->name);
+	ret = register_shrinker(&bc->shrink, "%s-btree_cache", c->name);
 	if (ret)
 		goto err;
 

fs/bcachefs/btree_key_cache.c

@@ -1042,7 +1042,7 @@ int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
 	bc->shrink.seeks		= 0;
 	bc->shrink.count_objects	= bch2_btree_key_cache_count;
 	bc->shrink.scan_objects		= bch2_btree_key_cache_scan;
-	if (register_shrinker(&bc->shrink, "%s/btree_key_cache", c->name))
+	if (register_shrinker(&bc->shrink, "%s-btree_key_cache", c->name))
 		return -BCH_ERR_ENOMEM_fs_btree_cache_init;
 	return 0;
 }