tracing/fastboot: use sched switch tracer from boot tracer

Impact: enhance boot trace output with scheduling events

Use the sched_switch tracer from the boot tracer.

We also can trace schedule events inside the initcalls.
Sched tracing is disabled after the initcall has finished and
then reenabled before the next one is started.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index d104d5b4..6bbc879 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -27,10 +27,14 @@
 
 void enable_boot_trace(void)
 {
+	if (pre_initcalls_finished)
+		tracing_start_cmdline_record();
 }
 
 void disable_boot_trace(void)
 {
+	if (pre_initcalls_finished)
+		tracing_stop_cmdline_record();
 }
 
 void reset_boot_trace(struct trace_array *tr)
@@ -45,6 +49,8 @@
 
 	for_each_cpu_mask(cpu, cpu_possible_map)
 		tracing_reset(tr, cpu);
+
+	sched_switch_trace.init(tr);
 }
 
 static void boot_trace_ctrl_update(struct trace_array *tr)