x86: hpet: Use proper destructor for delayed work

destroy_timer_on_stack() is hardly the right thing for a delayed
work. We leak a tracking object for the work itself when DEBUG_OBJECTS
is enabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20140323141940.034005322@linutronix.de


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>