kernel:wr_clocksource: replace clocksource_calc_mult_shift()

Instead of using clocksource_register() we use
clocksource_register_hz() as suggested

From kernel patch c7f798e3722610d486e951f04bbc00b6ba124d62
    clocksource: Get rid of clocksource_calc_mult_shift()

    No one is using this, so encourage the use of
    clocksource_register_hz/khz(), and drop this helper.

    Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
    [jstultz: tweaked commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>

Signed-off-by: Federico Vaga <federico.vaga@cern.ch>

kernel/wr_clocksource/wr_clocksource.c

@@ -109,7 +109,7 @@ static void wrcs_timer_fn(unsigned long unused)
 		return;
 	}
 
-	clocksource_register(&wrcs_cs);
+	clocksource_register_hz(&wrcs_cs, WRCS_FREQUENCY);
 	wrcs_is_registered = 1;
 	/* And don't restart the timer */
 }
@@ -122,8 +122,6 @@ static int wrcs_init(void)
 		return -EIO;
 	}
 
-	clocksource_calc_mult_shift(&wrcs_cs, WRCS_FREQUENCY, 1);
-
 	/* Fire the timer */
 	mod_timer(&wrcs_timer, jiffies + HZ);
 	return 0;