posix-cpu-timers: Use clock ID in posix_cpu_timer_rearm()

Extract the clock ID (PROF/VIRT/SCHED) from the clock selector and use it
as argument to the sample functions. That allows to simplify them once all
callers are fixed.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.245357769@linutronix.de

kernel/time/posix-cpu-timers.c

@@ -987,6 +987,7 @@ static void check_process_timers(struct task_struct *tsk,
  */
 static void posix_cpu_timer_rearm(struct k_itimer *timer)
 {
+	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
 	struct task_struct *p = timer->it.cpu.task;
 	struct sighand_struct *sighand;
 	unsigned long flags;
@@ -999,7 +1000,7 @@ static void posix_cpu_timer_rearm(struct k_itimer *timer)
 	 * Fetch the current sample and update the timer's expiry time.
 	 */
 	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
-		cpu_clock_sample(timer->it_clock, p, &now);
+		cpu_clock_sample(clkid, p, &now);
 		bump_cpu_timer(timer, now);
 		if (unlikely(p->exit_state))
 			return;
@@ -1025,7 +1026,7 @@ static void posix_cpu_timer_rearm(struct k_itimer *timer)
 			/* If the process is dying, no need to rearm */
 			goto unlock;
 		}
-		cpu_clock_sample_group(timer->it_clock, p, &now, true);
+		cpu_clock_sample_group(clkid, p, &now, true);
 		bump_cpu_timer(timer, now);
 		/* Leave the sighand locked for the call below.  */
 	}