Input: rotary_encoder - support binary encoding of states

It's not advisable to use this encoding, but to support existing devices
add support for this to the driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>