SurfaceFlinger: mFbFence initialization

MobC00383030
b/12487813

SurfaceFlinger crash is observed while connecting
to Wi-Fi display.

Note: change 14e8b01a
removed the initialization leading to the crash when
running through the HWC composition path.  Restore the
initialization to solve the problem.

Change-Id: I581defc7135ac512080c0da06a62b1dae7d218c4
Signed-off-by: mayank parshar <mayankp@broadcom.com>
Signed-off-by: Pierre Couillaud <pierre@broadcom.com>