Camera3: Update ZSL post-processing tags

Update ZSL processing tags according the still capture template
Also cache the request template to avoid extra cost of querying
into HAL every time.

Bug: 17463102
Change-Id: I2eeffefb0a4131c99a85dd3e4484cc6f0f025efa
diff --git a/services/camera/libcameraservice/device3/Camera3Device.h b/services/camera/libcameraservice/device3/Camera3Device.h
index b99ed7e..ec6bba1 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -174,6 +174,8 @@
 
     CameraMetadata             mDeviceInfo;
 
+    CameraMetadata             mRequestTemplateCache[CAMERA3_TEMPLATE_COUNT];
+
     uint32_t                   mDeviceVersion;
 
     enum Status {