clocksource/drivers/ti-32k: Prevent ftrace recursion

Currently ti-32k can be used as a scheduler clock. We properly marked
omap_32k_read_sched_clock() as notrace but we then call another
function ti_32k_read_cycles() that _wasn't_ notrace.

Having a traceable function in the sched_clock() path leads to a
recursion within ftrace and a kernel crash.

Fix this by adding notrace attribute to the ti_32k_read_cycles()
function.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Cc: daniel.lezcano@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20160922075621.3725-1-jszhang@marvell.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/clocksource/timer-ti-32k.c

@@ -65,7 +65,7 @@ static inline struct ti_32k *to_ti_32k(struct clocksource *cs)
 	return container_of(cs, struct ti_32k, cs);
 }
 
-static cycle_t ti_32k_read_cycles(struct clocksource *cs)
+static cycle_t notrace ti_32k_read_cycles(struct clocksource *cs)
 {
 	struct ti_32k *ti = to_ti_32k(cs);