sysctl: Replace void pointer with const pointer to ctl_table

sysctl: Replace void pointer with const pointer to ctl_table

* Replace void* data in the converter functions with a const struct
  ctl_table* table as it was only getting forwarding values from
  ctl_table->extra{1,2}.
* Remove the void* data in the do_proc_* functions as they already had a
  pointer to the ctl_table.
* Remove min/max structures do_proc_do{uint,int}vec_minmax_conv_param;
  the min/max values get passed directly in ctl_table.
* Keep min/max initialization in extra{1,2} in proc_dou8vec_minmax.
* The do_proc_douintvec was adjusted outside sysctl.c as it is exported
  to fs/pipe.c.

Signed-off-by: Joel Granados <joel.granados@kernel.org>