mfd: cros_ec: Load cros_ec_ucsi on supported ECs

Load cros_ec_ucsi driver if the ChromeOS EC implements
UCSI Platform Policy Manager (PPM).

Signed-off-by: Pavan Holla <pholla@chromium.org>
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
Link: https://lore.kernel.org/r/20240910101527.603452-8-ukaszb@chromium.org


Signed-off-by: Lee Jones <lee@kernel.org>