imx: timer: don't clear the GPT control register multiple times

There is no need to clear the control register 100 times in a
loop, a single zero write clears the register. I didn't find any
justification why clearing this register in a loop is needed
(no info in i.MX6 errata or GPT timer linux driver, linux driver
uses single write to clear this control register).

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Stefano Babic <sbabic@denx.de>

arch/arm/mach-imx/timer.c

@@ -74,8 +74,7 @@ int timer_init(void)
 	__raw_writel(GPTCR_SWR, &cur_gpt->control);
 
 	/* We have no udelay by now */
-	for (i = 0; i < 100; i++)
-		__raw_writel(0, &cur_gpt->control);
+	__raw_writel(0, &cur_gpt->control);
 
 	i = __raw_readl(&cur_gpt->control);
 	i &= ~GPTCR_CLKSOURCE_MASK;