Yama: mark local symbols as static

sparse complains that Yama defines functions and a variable as non-static
even though they don't exist in any header. Fix it by making them static.

Co-developed-by: Mukesh Ojha <[e-mail]>
Signed-off-by: Mukesh Ojha <[e-mail]>
Signed-off-by: Jann Horn <[e-mail]>
[kees: merged similar static-ness fixes into a single patch]
Link: https://lkml.kernel.org/r/[e-mail]
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Kees Cook <[e-mail]>
Signed-off-by: James Morris <[e-mail]>

security/yama/yama_lsm.c

···
  * yama_task_free - check for task_pid to remove from exception list
  * @task: task being removed
  */
-void yama_task_free(struct task_struct *task)
+static void yama_task_free(struct task_struct *task)
 {
 	yama_ptracer_del(task, task);
 }
···
  * Return 0 on success, -ve on error.  -ENOSYS is returned when Yama
  * does not handle the given option.
  */
-int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3,
+static int yama_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			   unsigned long arg4, unsigned long arg5)
 {
 	int rc = -ENOSYS;
···
  *
  * Returns 0 if following the ptrace is allowed, -ve on error.
  */
-int yama_ptrace_traceme(struct task_struct *parent)
+static int yama_ptrace_traceme(struct task_struct *parent)
 {
 	int rc = 0;
 
···
 static int zero;
 static int max_scope = YAMA_SCOPE_NO_ATTACH;
 
-struct ctl_path yama_sysctl_path[] = {
+static struct ctl_path yama_sysctl_path[] = {
 	{ .procname = "kernel", },
 	{ .procname = "yama", },
 	{ }