do_last: kill a rudiment of old ->d_revalidate() workaround

There used to be time when ->d_revalidate() couldn't return an error.
So intents code had lookup_instantiate_filp() stash ERR_PTR(error)
in nd->intent.open.filp and had it checked after lookup_hash(), to
catch the otherwise silent failures.  That had been introduced by
commit 4af4c52f34606bdaab6930a845550c6fb02078a4.  These days
->d_revalidate() can and does propagate errors back to callers
explicitly, so this check isn't needed anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -2183,11 +2183,6 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	path->dentry = dentry;
 	path->mnt = nd->path.mnt;
 
-	if (IS_ERR(nd->intent.open.file)) {
-		error = PTR_ERR(nd->intent.open.file);
-		goto exit_mutex_unlock;
-	}
-
 	/* Negative dentry, just create the file */
 	if (!dentry->d_inode) {
 		int mode = op->mode;