thermal: qpnp-temp-alarm: Configure TEMP ALARM in the shutdown path

Force the TEMP ALARM into FOLLOW_HW_EN mode in the system shutdown
path, to avoid leakage when device is powered-off.

CRs-Fixed: 1059981
Change-Id: I7017d7ecc9b75570c41a13c49ac67045052630e9
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>