hwc: Add conditional for use of retire fence

 * This patch is only in AOSP, and requires specific support in the
   kernel. Add a conditional for devices that want to use it.

Change-Id: I7e0b7ee0ea2f58b82db1adc28c6cdd9eb4db2156
Signed-off-by: bmc08gt <brandon.mcansh@gmail.com>