bcache: do not check if debug dentry is ERR or NULL explicitly on remove

debugfs_remove and debugfs_remove_recursive will check if the dentry
pointer is NULL or ERR, and will do nothing in that case.

Remove the check in cache_set_free and bch_debug_init.
Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/debug.c

@@ -249,7 +249,6 @@ void bch_debug_init_cache_set(struct cache_set *c)
 
 void bch_debug_exit(void)
 {
-	if (!IS_ERR_OR_NULL(bcache_debug))
 	debugfs_remove_recursive(bcache_debug);
 }
 

drivers/md/bcache/super.c

@@ -1510,7 +1510,6 @@ static void cache_set_free(struct closure *cl)
 	struct cache *ca;
 	unsigned int i;
 
-	if (!IS_ERR_OR_NULL(c->debug))
 	debugfs_remove(c->debug);
 
 	bch_open_buckets_free(c);