mfd: cros_ec_dev: Add missing mfd_remove_devices() call in remove

mfd: cros_ec_dev: Add missing mfd_remove_devices() call in remove

[ Upstream commit 18e294ddafaeb80a1e2e10c9bd750a6cb8388d5b ]

The driver adds different MFD child devices via mfd_add_devices() and
hence it is required to call mfd_remove_devices() to remove MFD child
devices.

Fixes: 5e0115581bbc ("cros_ec: Move cros_ec_dev module to drivers/mfd")
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>