ARM: 7560/1: SMP_TWD: use DIV_ROUND_CLOSEST() for periodic mode

The periodic mode is currently calculated by a simple division
but we should pay more attention to our integer arithmetics.
Also delete a comment that does not make any sense.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/smp_twd.c

@@ -42,10 +42,10 @@ static void twd_set_mode(enum clock_event_mode mode,
 
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
-		/* timer load already set up */
 		ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
 			| TWD_TIMER_CONTROL_PERIODIC;
-		__raw_writel(twd_timer_rate / HZ, twd_base + TWD_TIMER_LOAD);
+		__raw_writel(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
+			twd_base + TWD_TIMER_LOAD);
 		break;
 	case CLOCK_EVT_MODE_ONESHOT:
 		/* period set, and timer enabled in 'next_event' hook */