hfs: convert extents_lock in a mutex

Apple Macintosh file system: The semaphore extens_lock is used as a mutex.
Convert it to the mutex API

Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index f6621a7..9b9d639 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -40,7 +40,7 @@
 	{
 	struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
 	HFS_I(tree->inode)->flags = 0;
-	init_MUTEX(&HFS_I(tree->inode)->extents_lock);
+	mutex_init(&HFS_I(tree->inode)->extents_lock);
 	switch (id) {
 	case HFS_EXT_CNID:
 		hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,