platform/chrome: cros_ec_lightbar: Reduce ligthbar get version command

By default, the lightbar commands are set to the biggest lightbar command
and response. That length is greater than 128 bytes and may not work on
all machines. But all EC are probed for lightbar by sending a get version
request. Set that request size precisely.

Before the command would be:

  cros_ec_cmd: version: 0, command: EC_CMD_LIGHTBAR_CMD, outsize: 194, insize: 128, result: 0

Afer:

  cros_ec_cmd: version: 0, command: EC_CMD_LIGHTBAR_CMD, outsize: 1, insize: 8, result: 0

Fixes: a8411784 ("mfd: cros_ec: Use a zero-length array for command data")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>