chgstv2: call sustain_battery_soc without checking previous states
chgstv2: call sustain_battery_soc without checking previous states

When we enalbe battery sustain after battery returns that it is full,
we need to add this condition for sustain_battery_soc(). Also, add this
test condition for battery sustainer.

BUG=b:188457962
BRANCH=none
TEST=make sure the battery sustain works when enabling it after battery
returns that it is full. Also, make sure that "make run-sbs_charging_v2"
pass.

Signed-off-by: Tommy Chung <6120d22c63496c33c3bb182026a6e985639be44d@quanta.corp-partner.google.com>
Change-Id: If10b9fd0264717abfb7cdbb7ddc947b370291895
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3070946
Reviewed-by: Devin Lu <052fe648504800b810f29702ef4f3db83fad68bf@quantatw.com>
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Tested-by: Daisuke Nojiri <fd5f93af191bf7e8f73ea71cc3c0f66b41b1dd49@chromium.org>
Commit-Queue: Daisuke Nojiri <fd5f93af191bf7e8f73ea71cc3c0f66b41b1dd49@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec