gpio: add polarity and pull up/down config flags

This adds to the configuration flags for GPIO:

() Indicates the polarity of the pin, whether it should be
   normal or inversed.

() Enables pull up/pull down for the pin.

Change-Id: I2b0c57e5a539208aff7aeb4ea53050134ab404fd
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
1 file changed