xfs: kill VN_DIRTY()

Only one user of the macro and the dirty mapping check is redundant
so just get rid of it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 1a5e068..fea3c92 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1635,7 +1635,7 @@
 		truncated = xfs_iflags_test_and_clear(ip, XFS_ITRUNCATED);
 		if (truncated) {
 			xfs_iflags_clear(ip, XFS_IDIRTY_RELEASE);
-			if (VN_DIRTY(VFS_I(ip)) && ip->i_delayed_blks > 0) {
+			if (ip->i_delayed_blks > 0) {
 				error = filemap_flush(VFS_I(ip)->i_mapping);
 				if (error)
 					return error;