baylibre-acme: gpio: Don't set direction in get/set functions.

GPIO direction should be set once right after exporting. There's no need
to reset it again - in fact it's a bug which causes the probe to be reset
every time the value is read/set and gives incorrect results when reading
the GPIO values with direction == 'in'.

Signed-off-by: Bartosz Golaszewski <redacted>