battery: Current rate must be positive.
battery: Current rate must be positive.

ACPI disallows a negative current rate.
Use the absolute rate, and rely on the flags to indicate
charging or discharging.

BUG=b:227275730
TEST=zmake build nivviks
BRANCH=none

Signed-off-by: Andrew McRae <44ad1424cfc8411c96d9181798ca41ae55709dfb@google.com>
Change-Id: I90e05ccd39442aa8e65e06cf7848d05a32879742
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3577321
Reviewed-by: Peter Marheine <ef0b2c492edde94778d7465bfbaeed52c5be6858@chromium.org>

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