glkrvp: Discharge on AC when battery almost full
glkrvp: Discharge on AC when battery almost full

In the case of almost full battery, without this
change the battery will keep charging even
if charging is not allowed when external power
is kept attached.

BUG=b:71364739
BRANCH=master
TEST=On glkrvp, let battery charge to 100% and verify after that
     it starts discharging to 95% and then starts charging back.

Change-Id: I71935f795909d11ad93fd56caaa3683b54104c65
Signed-off-by: Divya Sasidharan <dba62b20a5027527f6399518550d13252dee26fc@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/927798
Commit-Ready: Divya S Sasidharan <dba62b20a5027527f6399518550d13252dee26fc@intel.com>
Tested-by: Divya S Sasidharan <dba62b20a5027527f6399518550d13252dee26fc@intel.com>
Reviewed-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Reviewed-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>

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