camera: Allow hardware/camera.h header to be overridden

Change-Id: I715ba261de0b01e61cbfe7cacd567a9f511fb8cb

Signed-off-by: artas182x <artas182x@gmail.com>
Merge pull request #1 from artas182x/aosp-5.0

camera: Allow hardware/camera.h header to be overridden