inode->i_op is never NULL

We used to have rather schizophrenic set of checks for NULL ->i_op even
though it had been eliminated years ago.  You'd need to go out of your
way to set it to NULL explicitly _and_ a bunch of code would die on
such inodes anyway.  After killing two remaining places that still
did that bogosity, all that crap can go away.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/nommu.c b/mm/nommu.c
index 7695dc8..1c28ea3 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -86,7 +86,7 @@
 	i_size_write(inode, offset);
 
 out_truncate:
-	if (inode->i_op && inode->i_op->truncate)
+	if (inode->i_op->truncate)
 		inode->i_op->truncate(inode);
 	return 0;
 out_sig: