battery: Set host's low battery shutdown SoC to 4%
battery: Set host's low battery shutdown SoC to 4%

Currently, the host's low battery shutdown SoC is 3% by default but
most boards are configured to 4%. This patch changes the default value
to 4% so that we require only minority boards to customize it.

BUG=b:191837893, b:189737806
BRANCH=None
TEST=Storo using battfake EC command.

Change-Id: I69ed5d8cc8c0d1e321d79c5eae26a9c21624a4ea
Signed-off-by: Daisuke Nojiri <fd5f93af191bf7e8f73ea71cc3c0f66b41b1dd49@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2998509
Reviewed-by: Aseda Aboagye <12c9b286316a940fd31c24070da5ab64cdd4d0e7@chromium.org>

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