ktime: Kill non-scalar ktime_t implementation for 2038

The non-scalar ktime_t implementation is basically a timespec
which has to be changed to support dates past 2038 on 32bit
systems.

This patch removes the non-scalar ktime_t implementation, forcing
the scalar s64 nanosecond version on all architectures.

This may have additional performance overhead on some 32bit
systems when converting between ktime_t and timespec structures,
however the majority of 32bit systems (arm and i386) were already
using scalar ktime_t, so no performance regressions will be seen
on those platforms.

On affected platforms, I'm open to finding optimizations, including
avoiding converting to timespecs where possible.

[ tglx: We can now cleanup the ktime_t.tv64 mess, but thats a
  different issue and we can throw a coccinelle script at it ]

Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>

kernel/time/timekeeping.c

@@ -344,11 +344,8 @@ ktime_t ktime_get(void)
 		nsecs = timekeeping_get_ns(tk) + tk->wall_to_monotonic.tv_nsec;
 
 	} while (read_seqcount_retry(&timekeeper_seq, seq));
-	/*
-	 * Use ktime_set/ktime_add_ns to create a proper ktime on
-	 * 32-bit architectures without CONFIG_KTIME_SCALAR.
-	 */
-	return ktime_add_ns(ktime_set(secs, 0), nsecs);
+
+	return ktime_set(secs, nsecs);
 }
 EXPORT_SYMBOL_GPL(ktime_get);