[XFS] move sync code to its own file

The sync code in XFS is spread around several files. While it used to make
sense to have such a distribution, the code is about to be cleaned up and
so centralising it in one spot as the first step makes sense.

SGI-PV: 988139

SGI-Modid: xfs-linux-melb:xfs-kern:32282a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 75b2be7..51b87de 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -107,6 +107,7 @@
 				   xfs_iops.o \
 				   xfs_lrw.o \
 				   xfs_super.o \
+				   xfs_sync.o \
 				   xfs_vnode.o \
 				   xfs_xattr.o)