mutex: make 0/1 FIO_MUTEX_LOCKED and FIO_MUTEX_UNLOCKED

Makes the API look cleaner.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/filehash.c b/filehash.c
index 1bb1eb2..392464e 100644
--- a/filehash.c
+++ b/filehash.c
@@ -107,5 +107,5 @@
 	for (i = 0; i < HASH_BUCKETS; i++)
 		INIT_FLIST_HEAD(&file_hash[i]);
 
-	hash_lock = fio_mutex_init(1);
+	hash_lock = fio_mutex_init(FIO_MUTEX_UNLOCKED);
 }