Revert "clockevents: Set noop handler in clockevents_exchange_device()"

This reverts commit de28f25e.

It results in resume problems for various people. See for example

  http://thread.gmane.org/gmane.linux.kernel/1233033
  http://thread.gmane.org/gmane.linux.kernel/1233389
  http://thread.gmane.org/gmane.linux.kernel/1233159
  http://thread.gmane.org/gmane.linux.kernel/1227868/focus=1230877

and the fedora and ubuntu bug reports

  https://bugzilla.redhat.com/show_bug.cgi?id=767248
  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/904569



which got bisected down to the stable version of this commit.

Reported-by: Jonathan Nieder <jrnieder@gmail.com>
Reported-by: Phil Miller <mille121@illinois.edu>
Reported-by: Philip Langdale <philipl@overt.org>
Reported-by: Tim Gardner <tim.gardner@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg KH <gregkh@suse.de>
Cc: stable@kernel.org    # for stable kernels that applied the original
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>