clocksource: dw_apb_timer_of: Do not trace read_sched_clock

We do not need to trace read_sched_clock function,
so add notrace attribute for this function.

Signed-off-by: Yang Wei <Wei.Yang@windriver.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index 2a2ea27..d305fb0 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -106,7 +106,7 @@
 	sched_rate = rate;
 }
 
-static u64 read_sched_clock(void)
+static u64 notrace read_sched_clock(void)
 {
 	return ~__raw_readl(sched_io_base);
 }