fs: remove unlikely() from WARN_ON() condition

"unlikely(WARN_ON(x))" is excessive. WARN_ON() already uses unlikely()
internally.

Link: http://lkml.kernel.org/r/20190829165025.15750-5-efremov@linux.com
Signed-off-by: Denis Efremov <efremov@linux.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/open.c

@@ -776,7 +776,7 @@ static int do_dentry_open(struct file *f,
 		f->f_mode |= FMODE_ATOMIC_POS;
 
 	f->f_op = fops_get(inode->i_fop);
-	if (unlikely(WARN_ON(!f->f_op))) {
+	if (WARN_ON(!f->f_op)) {
 		error = -ENODEV;
 		goto cleanup_all;
 	}