ftrace: remove wakeup from function trace

trace_function is called by mcount and calling wake_up from that
can have unpredictable results. This patch removes the wakeup from
trace_function.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>