thermal: Add Support for enabling and disabling tsens trip

Add new API to enable or disable the kernel client's trip
threshold request. The enable or disable trip threshold requests
from different kernel clients and userspace client will
activate/deactivate the corresponding clients threshold request.

Modify thermal sys framework to include only the active
thresholds from clients to determine the current trip
thresholds for tsens.

CRs-Fixed: 561775
Change-Id: I304ac00daa8a0a1a68b60153c29ee6cb5c3507b1
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>