The x86 timer interrupt handler is the only handler not traced in the

The x86 timer interrupt handler is the only handler not traced in the
irq/irq_handler_{entry|exit} trace events.

Add tracepoints to the interrupt handler to trace it.

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>