hfs: simplify a bit checking for R/O

We have the following pattern in 2 places in HFS

if (!RDONLY)
	hfs_mdb_commit();

This patch pushes the RDONLY check down to 'hfs_mdb_commit()'. This will
make the following patches a bit simpler.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index 47e4119..0730135 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -53,8 +53,7 @@
 	sb->s_dirt = 0;
 
 	/* sync everything to the buffers */
-	if (!(sb->s_flags & MS_RDONLY))
-		hfs_mdb_commit(sb);
+	hfs_mdb_commit(sb);
 }
 
 static int hfs_sync_fs(struct super_block *sb, int wait)