ppdev: convert to y2038 safe

The y2038 issue for ppdev is changes of timeval in the ioctl
(PPSETTIME and PPGETTIME). The size of struct timeval changes from
8bytes to 16bytes due to the changes of time_t. It lead to the
changes of the command of ioctl, e.g. for PPGETTIME, We have:

on 32-bit (old): 0x80087095
on 32-bit (new): 0x80107095
on 64-bit      : 0x80107095

This patch define these two ioctl commands to support the 32bit
and 64bit time_t application at the same time. And, introduce
pp_set_timeout to remove some duplicated code.

Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>