time: Change k_clock clock_getres() to use timespec64

struct timespec is not y2038 safe on 32 bit machines.  Replace uses of
struct timespec with struct timespec64 in the kernel. The syscall
interfaces themselves will be changed in a separate series.

The clock_getres() interface has also been changed to use timespec64 even
though this particular interface is not affected by the y2038 problem. This
helps verification for internal kernel code for y2038 readiness by getting
rid of time_t/ timeval/ timespec completely.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: y2038@lists.linaro.org
Cc: john.stultz@linaro.org
Cc: arnd@arndb.de
Link: http://lkml.kernel.org/r/1490555058-4603-5-git-send-email-deepa.kernel@gmail.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>