sysctl: remove redundant ret assignment

Subsequent if judgments will assign new values to ret, so the statement
here should be deleted

The clang_analyzer complains as follows:

  fs/proc/proc_sysctl.c:
  Value stored to 'ret' is never read

Link: https://lkml.kernel.org/r/20211230063622.586360-1-luo.penghao@zte.com.cn
Signed-off-by: luo penghao <luo.penghao@zte.com.cn>
Reported-by: Zeal Robot <zealci@zte.com.cn>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/proc_sysctl.c

@@ -1053,7 +1053,6 @@ static int sysctl_follow_link(struct ctl_table_header **phead,
 	struct ctl_dir *dir;
 	int ret;
 
-	ret = 0;
 	spin_lock(&sysctl_lock);
 	root = (*pentry)->data;
 	set = lookup_header_set(root);