ACPI: thermal: use round_jiffies when thermal zone polling is enabled

Properly functioning systems do not use thermal zone polling,
they use event-based notification.

However, some users enable periodic thermal zone polling
to work around bugs on their platforms, and at least one
platform exists with a real _TZP that requests polling.

While thermal zone polling (_TZP) is specified in units to 0.1 seconds,
it actually has a maximum granularity of 1 second.  Thus, we can safely
round up the _TZP timeout to occur on the next 1-second boundary.
This will batch it with other 1-second-granularity timers in the
system and thus potentially extend processor idle duration.

Note that the same timer is used both for _TZP
and for passive processor thermal throttling.
We can not round up the timeout when it is used
for passive thermal throttling.

Also, we can not make this a deferrable timer,
as temperature is just as relevant during idle
as it is during non-idle.

Signed-off-by: Len Brown <len.brown@intel.com>