Update camera HAL & implement libcamera2

* camera HAL adapted from Evervolv:
  https://github.com/Evervolv/android_hardware_qcom_camera/tree/jellybean-4.1.2

* Set TARGET_PREBUILT_LIBCAMERA := true to build only the camera HAL.

* Implements TARGET_CAMERA_SENSOR_MP_SIZE to specify default preview
  size. Defaults to 2 if unset.

Note: libcamera source requires Froyo version of liboemcamera.so.

Conflicts:
	prebuilt/etc/media_profiles.xml

(cherry picked from commit 92f8ffeb8f855646fdb2ead8bd5aa3f74f3d02e1)

Change-Id: Iec0823de416668e8991d0fdfecd6792a85fbf0bb