board: gateworks: venice: remove forced enable of GSC thermal protection

The Gateworks System Controller thermal protection feature will disable
the board primary power supply if the on-board temperature sensor
reaches 86C. In many cases this could occur before the temperature
critical components such as CPU, DRAM, eMMC, and power supplies have
reached their max temperature.

Remove the forced re-enable of thermal protection so that users can
knowingly disable it.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>