honeybuns: Allow 20v charging
honeybuns: Allow 20v charging

Previous HW didn't correctly support 20V charging. The HW has been
corrected and now there is no need to keep 20V mode disabled in FW.

BUG=chrome-os-partner:48217
BRANCH=none
TEST=Tested in the lab by jguerin@ against Samus

Change-Id: I952872affb302c7aa2ddb97466cd5ce459d2ac54
Signed-off-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/315219
Reviewed-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Reviewed-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec