gralloc: Fix caching for rarely read/write flags

GRALLOC_USAGE_SW_WRITE_RARELY and GRALLOC_USAGE_SW_READ_RARELY
need to be compared directly since they share bits with
GRALLOC_USAGE_SW_WRITE_OFTEN and GRALLOC_USAGE_SW_READ_OFTEN.

CRs-fixed: 569559

Change-Id: I52692027033e1036e3ad960b9e03dd8ee60b4111
hwc: Add support for Secure display

- Identify secure display layer in the hwc_list
- Need to set both SECURE_OVERLAY and SECURE_DISPLAY flags for the secure
  display layer
- Disable idle timeout for secure display usecase, as GPU should not be
  accessing secure display layer

Change-Id: I555910db77c466b5e103b24b4f0ec7f47bb210a5
hwc: remove unblanking fb from openframebufferdevice

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

Change-Id: Ifaed119503c74b5a75ffd6694d3508c4c15dfb60
Conflicts:
	common.mk
	libhwcomposer/hwc_utils.cpp

Change-Id: Icc0f7cf6c8b5762083417c3386dfdfad50322ba3