Input: rotary-encoder - set gpio direction for each requested gpio

Even with the correct pin mux settings, you still need to explicitly
set the gpio direction. Call gpio_direction_input() after each
requested gpio.

Signed-off-by: Andrew Clayton <andrew@digital-domain.net>
Signed-off-by: Mark Somerville <mark@scottishclimbs.com>
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>