ceph: fix sparse endian warning

Use the __le macro, even though for -1 it doesn't matter.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 1bd57c8..fc8aff4 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -52,7 +52,7 @@
 	req->r_fmode = ceph_flags_to_mode(flags);
 	req->r_args.open.flags = cpu_to_le32(flags);
 	req->r_args.open.mode = cpu_to_le32(create_mode);
-	req->r_args.open.preferred = -1;
+	req->r_args.open.preferred = cpu_to_le32(-1);
 out:
 	return req;
 }