libadf: support ADF_{POST,SIMPLE_POST}_CONFIG_V2 ioctls

adf_{device,interface_simple}_post_v2 let the client choose what kind of
fence is returned from the kernel:

* ADF_COMPLETE_FENCE_NONE: no fence is returned
* ADF_COMPLETE_FENCE_PRESENT: the returned fence fires when the
  specified configuration appears on the screen
* ADF_COMPLETE_FENCE_RELEASE: the returned fence fires when the
  specified configuration is removed from the screen

The "V2" calls with fence type ADF_COMPLETE_FENCE_RELEASE are functionally
equivalent to "V1" calls.

Test: included gtest (on Nexus 9)
Change-Id: I36190d1b6cea0fbaed2af3ad64fa4729200c5520
Signed-off-by: Greg Hackmann <ghackmann@google.com>