Thermal: Disable SoC throttling when Charging

SOC Based throttling is disabled when charging is enabled.
Throttling is re-enabled once charging is removed.

Bug: 131314951
Test: Use emul_temp and battery/capacity to emulate
      condition for checking if SOC thermal zone is
      disabled/enabled.
Change-Id: Ib3dc52eaf1d6ec0ff4d8e87e134d839385e69948
Signed-off-by: George Lee <geolee@google.com>