asm-h8300: parentheses around definition CLOCK_TICK_RATE

Some places where CLOCK_TICK_RATE may be used incorrectly:

arch/arm/mach-mx3/time.c:125: __raw_writel((v / CLOCK_TICK_RATE) - 1, MXC_GPT_GPTPR);

drivers/watchdog/davinci_wdt.c:103:     timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff);
drivers/watchdog/davinci_wdt.c:105:     timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32);
drivers/watchdog/ks8695_wdt.c:64:       unsigned long tval = wdt_time * CLOCK_TICK_RATE;

I'm not sure whether this definition is used there, but adding parentheses should be good anyways.
--
Add parentheses to prevent operator precedence errors

---

index 2041314..23e6701 100644
@@ -6,7 +6,7 @@
 #ifndef _ASM_H8300_TIMEX_H
 #define _ASM_H8300_TIMEX_H
 
-#define CLOCK_TICK_RATE CONFIG_CPU_CLOCK*1000/8192 /* Timer input freq. */
+#define CLOCK_TICK_RATE (CONFIG_CPU_CLOCK*1000/8192) /* Timer input freq. */
 
 typedef unsigned long cycles_t;
 extern short h8300_timer_count;