libcopybit: Remove usage of C2D_NO_BILINEAR_BIT

Remove usage of C2D_NO_BILINEAR_BIT in the config mask.
This enables using the BILINEAR filter for scaling and
improves the image quality

Change-Id: Ic9b61fe3ed5b16e63971fe542928640a13d92764
CRs-fixed: 453925
hwc: Add support for clearing with c2d

When blending translucent layers or transitioning with c2d,
sometimes the frame is blended with stale framebuffer content.
Clear the frame with C2D fill surface before drawing.

CRs-fixed: 462461
Change-Id: I1dca477fe88d77f4f0fa4846b155404f348e911d

Conflicts:
	libcopybit/copybit_c2d.cpp