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/filesetup.c b/filesetup.c
index 371b405..6277f0f 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -1006,7 +1006,7 @@
 		f->lock = fio_mutex_rw_init();
 		break;
 	case FILE_LOCK_EXCLUSIVE:
-		f->lock = fio_mutex_init(1);
+		f->lock = fio_mutex_init(FIO_MUTEX_UNLOCKED);
 		break;
 	default:
 		log_err("fio: unknown lock mode: %d\n", td->o.file_lock_mode);