camera: use new ION APIs for cache operations.

This change incorporates the API changes for cache operations.
The cache operations have now been moved to a custom ioctl, with
a new custom_data argument.

Change-Id: I81f0fdb6a7556b433bac6e7ccaa78922aabecdb2
(cherry picked from commit 40bc6b9491e7dae982ba6c886ebec039293e4c08)
Sync with jb_chocolate_rb4.1
Revert "camera: allocate histogram stat buffers and send to daemon"

This reverts commit bfe4d128e1b92d5afab2df8d53290979f969853d.

Conflicts:
	QCameraHWI.cpp
	QCameraHWI.h
	QCameraHWI_Parm.cpp
	QCameraHWI_Preview.cpp
	QCameraHWI_Still.cpp
Revert "Revert "camera: allocate histogram stat buffers and send to daemon""

This reverts commit 713f5f3703f86efc9a860df9b79e8ae2e80815cf.