ARM: highbank: fix get_tbclk value to timer rate

get_tbclk should return the timer's frequency, not CONFIG_SYS_HZ.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>

arch/arm/cpu/armv7/highbank/timer.c

@@ -124,5 +124,5 @@ ulong get_timer_masked(void)
 
 ulong get_tbclk(void)
 {
-	return CONFIG_SYS_HZ;
+	return SYSTIMER_RATE;
 }