ARM: ensure all sched_clock() implementations are notrace marked

ftrace requires sched_clock() to be notrace.  Ensure that all
implementations are so marked.  Also make sure that they include
linux/sched.h

Also ensure OMAP clocksource read functions are marked notrace as
they're used for sched_clock() too.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Tested-by: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: Eric Miao <eric.y.miao@gmail.com>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/plat-iop/time.c b/arch/arm/plat-iop/time.c
index 4332dc4..d03a932 100644
--- a/arch/arm/plat-iop/time.c
+++ b/arch/arm/plat-iop/time.c
@@ -17,6 +17,7 @@
 #include <linux/interrupt.h>
 #include <linux/time.h>
 #include <linux/init.h>
+#include <linux/sched.h>
 #include <linux/timex.h>
 #include <linux/io.h>
 #include <linux/clocksource.h>
@@ -52,7 +53,7 @@
 /*
  * IOP sched_clock() implementation via its clocksource.
  */
-unsigned long long sched_clock(void)
+unsigned long long notrace sched_clock(void)
 {
 	cycle_t cyc = iop_clocksource_read(NULL);
 	struct clocksource *cs = &iop_clocksource;