jfs: Add missing set_freezable() for freezable kthread

The kernel thread function jfs_lazycommit() and jfs_sync() invoke the
try_to_freeze() in its loop. But all the kernel threads are no-freezable
by default. So if we want to make a kernel thread to be freezable, we have
to invoke set_freezable() explicitly.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

fs/jfs/jfs_txnmgr.c

@@ -2702,6 +2702,7 @@ int jfs_lazycommit(void *arg)
 	unsigned long flags;
 	struct jfs_sb_info *sbi;
 
+	set_freezable();
 	do {
 		LAZY_LOCK(flags);
 		jfs_commit_thread_waking = 0;	/* OK to wake another thread */
@@ -2884,6 +2885,7 @@ int jfs_sync(void *arg)
 	struct jfs_inode_info *jfs_ip;
 	tid_t tid;
 
+	set_freezable();
 	do {
 		/*
 		 * write each inode on the anonymous inode list