The octsimtest board can control the card-insert contact of the OCTSIM
under test via an external I2C gpio multiplexer; let's add support for
that.
Change-Id: I8c9b0c3d862a967832134b24252577739182da62
* driver should not have hard-coded understanding about I/O directions
* board code should pass the I/O direction to driver
* board code should use the correct I/O directions (A0..7, B0: output)
Change-Id: Id4a8e012a33cee01bb489e612e17920760b9be59