time: Change k_clock clock_get() 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.

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/1490555058-4603-4-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/timekeeping.h

@@ -258,6 +258,11 @@ static inline void timekeeping_clocktai(struct timespec *ts)
 	*ts = ktime_to_timespec(ktime_get_clocktai());
 }
 
+static inline void timekeeping_clocktai64(struct timespec64 *ts)
+{
+	*ts = ktime_to_timespec64(ktime_get_clocktai());
+}
+
 /*
  * RTC specific
  */