perf_counter: generic context switch event

Impact: cleanup

Use the generic software events for context switches.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Orig-LKML-Reference: <20090319194233.283522645@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -2900,14 +2900,8 @@ unsigned long nr_active(void)
 
 /*
  * Externally visible per-cpu scheduler statistics:
- * cpu_nr_switches(cpu) - number of context switches on that cpu
  * cpu_nr_migrations(cpu) - number of migrations into that cpu
  */
-u64 cpu_nr_switches(int cpu)
-{
-	return cpu_rq(cpu)->nr_switches;
-}
-
 u64 cpu_nr_migrations(int cpu)
 {
 	return cpu_rq(cpu)->nr_migrations_in;