mfd: cros_ec: Fix the comment on cros_ec_remove()

This comment was incorrect, so update it.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>