sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table)

Remove the 'table' argument from set_ownership as it is never used. This
change is a step towards putting "struct ctl_table" into .rodata and
eventually having sysctl core only use "const struct ctl_table".

The patch was created with the following coccinelle script:

  @@
  identifier func, head, table, uid, gid;
  @@

  void func(
    struct ctl_table_header *head,
  - struct ctl_table *table,
    kuid_t *uid, kgid_t *gid)
  { ... }

No additional occurrences of 'set_ownership' were found after doing a
tree-wide search.

Reviewed-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Joel Granados <j.granados@samsung.com>