thermal: core: treat correctly the return value of *scanf calls

This patch checks the return value of all calls to *scanf.
The check is to simply match the number of expect inputs.

The current code does not do any recovery in case the
number of treated inputs are different than the expected.
Therefore, keeping the same behavior.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>