CameraService: Remove device HALv2 support, other cleanup

HALv2 only ever shipped with Nexus 10, and has been fully superceded by
HALv3. Remove it to allow for various code simplifications and cleanup.

- Remove Camera2Device
- Remove various special-case codepaths for supporting Camera2Device
- Remove CameraDeviceFactory, since it only creates Camera3Devices now
- Remove BurstCapture and associated CaptureSequence/Parameters code
- Remove old ZslProcessor and simplify ZslProcessor hierarchy to be
  just ZslProcessor3, which is renamed to just ZslProcessor
- Add service-init-time check for unsupported device versions
- Fix assorted compiler warnings, some old, some new
- Remove references to HALv2 when possible

Bug: 25866588
Change-Id: Ia1063264d315f9b742ec5cdd0483539310894f5e
diff --git a/services/camera/libcameraservice/common/Camera2ClientBase.h b/services/camera/libcameraservice/common/Camera2ClientBase.h
index 220c5ad..53122dc 100644
--- a/services/camera/libcameraservice/common/Camera2ClientBase.h
+++ b/services/camera/libcameraservice/common/Camera2ClientBase.h
@@ -125,7 +125,7 @@
     // that mBinderSerializationLock is locked when they're called
     mutable Mutex         mBinderSerializationLock;
 
-    /** CameraDeviceBase instance wrapping HAL2+ entry */
+    /** CameraDeviceBase instance wrapping HAL3+ entry */
 
     const int mDeviceVersion;
     sp<CameraDeviceBase>  mDevice;