get rid of open-coded S_ISREG(), etc.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index f011ed2..74fd747 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -870,7 +870,7 @@
 	} else if (ceph_snap(dir) == CEPH_NOSNAP) {
 		dout("unlink/rmdir dir %p dn %p inode %p\n",
 		     dir, dentry, inode);
-		op = ((dentry->d_inode->i_mode & S_IFMT) == S_IFDIR) ?
+		op = S_ISDIR(dentry->d_inode->i_mode) ?
 			CEPH_MDS_OP_RMDIR : CEPH_MDS_OP_UNLINK;
 	} else
 		goto out;