xfs: fix missing header includes

Some of the xfs source files are missing header includes, so add them
back.  Sparse complains about non-static functions that don't have a
forward declaration anywhere.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_symlink.c

@@ -17,6 +17,7 @@
 #include "xfs_bmap.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_quota.h"
+#include "xfs_symlink.h"
 #include "xfs_trans_space.h"
 #include "xfs_trace.h"
 #include "xfs_trans.h"