ACPI: thermal: Use white space more consistently

The usage of white space in the ACPI thermal driver is not very
consistent, so improve that a bit.

While at it, add missing braces to if()/else in a few places.

No functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>