thermal: enable thermal shutdown

Lower thermal shutdown temeprature to 55 degC to renable
shutdown for all HW revs and usecases

Bug: 204522715
Test: build and boot on device. Run a workload and check
thermal shutdown
Signed-off-by: Sayanna Chandula <sayanna@google.com>
Change-Id: I10ca928cf8639f279b9dcb1d609d0bb8c7ed2c29