power: qcom: ea: Fix uninitialized temperature and cpu variable

In update_userspace_power, incorrect cpumask could cause the function to
use uninitialized cpu variable. Initialize it to -1 at the beginning of
the function and treat unmodified value as error condition.

Change-Id: Ieccdc3f54f9c9f2cecc6b8578400c6fe44333177
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>
Signed-off-by: Albert I <krascgq@outlook.co.id>