hwc: Do not use fb handle in hwc_prepare

Do not use fb handle in prepare. Use displayFrame for dimensions,
align them and hardcode format

Change-Id: I5c494a74a807d3a52a1c88257494b58c583700f5
hwcomposer : Fix copybit render buffer fence usage.

Fixing array size to hold fence fd to count of render
buffers used in copybit, and use it to store
fence of corresponding render buffer at the index.

Change-Id: Ic5e7f264c2a81ded2a0f61ef138e59a093b0023a

Conflicts:
	libhwcomposer/hwc_copybit.cpp
hwc: remove unblanking fb from openframebufferdevice

- unblaking fb is done as part of surface flinger initialization
  so its not required here

Change-Id: Ifaed119503c74b5a75ffd6694d3508c4c15dfb60