pwm: cros-ec: Don't care about consumers in .get_state()

pwm: cros-ec: Don't care about consumers in .get_state()

The get_state() callback is never called (in a visible way) after there
is a consumer for a pwm device. The core handles loosing the information
about duty_cycle just fine.

Simplify the driver accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20240607084416.897777-6-u.kleine-koenig@baylibre.com
[Drop kdoc comment for channel to make W=1 builds happy]
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>