thermal/core: Fix lockdep_assert() warning

The function thermal_zone_device_is_enabled() must be called with the
thermal zone lock held. In the resume path, it is called without.

As the thermal_zone_device_is_enabled() is also checked in
thermal_zone_device_update(), do the check in resume() function is
pointless, except for saving an extra initialization which does not
hurt if it is done in all the cases.

Fixes: ca48ad71717dd ("thermal/core: Move the mutex inside the thermal_zone_device_update() function")
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>