thermal: pm8xxx-tm: Use delayed_work task for temp alarm status reading

Use a delayed_work task to wait at least 40 ms in order for the
temp alarm status value to be updated after the TEMP_STAT IRQ
goes high.  Also remove IRQ enable and disable calls in the ISR
since the work item can only be enqueued once before it is run.

Change-Id: Ib5f13d0e82258b399749de96152c081d71981909
Signed-off-by: David Collins <collinsd@codeaurora.org>