[WATCHDOG] Use DIV_ROUND_UP() macro in the coh901327 WDT

I saw Julia Lawalls various commits fixing up the use of rounding
macros and since my already submitted patch was not caught in this
I took it upon myself to fix it up for this driver as well.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/coh901327_wdt.c

@@ -110,7 +110,7 @@ static void coh901327_enable(u16 timeout)
 	 * Wait 3 32 kHz cycles for it to take effect
 	 */
 	freq = clk_get_rate(clk);
-	delay_ns = (1000000000 + freq - 1) / freq; /* Freq to ns and round up */
+	delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */
 	delay_ns = 3 * delay_ns; /* Wait 3 cycles */
 	ndelay(delay_ns);
 	/* Enable the watchdog interrupt */