This patch makes use of cros_ec_cmd_xfer_status() instead of
cros_ec_cmd_xfer(). In this case the change is trivial and the only
reason to do it is because we want to make cros_ec_cmd_xfer() a private
function for the EC protocol and let people only use the
cros_ec_cmd_xfer_status() to return Linux standard error codes.
Signed-off-by: NEnric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: NPrashant Malani <pmalani@chromium.org>