board/cogent/lcd.c: fix syntax error

Fix error detected by cppcheck:

[board/cogent/lcd.c:237]: (error) Invalid number of character (()
when these macros are defined:
'CONFIG_SHOW_ACTIVITY;CONFIG_STATUS_LED'.

Signed-off-by: Wolfgang Denk <wd@denx.de>
diff --git a/board/cogent/lcd.c b/board/cogent/lcd.c
index 8e90f98..05ffc4d 100644
--- a/board/cogent/lcd.c
+++ b/board/cogent/lcd.c
@@ -234,7 +234,7 @@
 void board_show_activity (ulong timestamp)
 {
 #ifdef CONFIG_STATUS_LED
-	if ((timestamp % (CONFIG_SYS_HZ / 2) == 0)
+	if ((timestamp % (CONFIG_SYS_HZ / 2)) == 0)
 		lcd_heartbeat ();
 #endif
 }