camera_common: add torch mode APIs for flashlight

Add torch mode APIs to support flashlight without opening any
camera devices.

Bug: 2682206
Change-Id: Ida46bb878962caf305f3e97051b15e0465fe8c02
diff --git a/modules/camera/CameraHAL.cpp b/modules/camera/CameraHAL.cpp
index 6f64a0d..06f308f 100644
--- a/modules/camera/CameraHAL.cpp
+++ b/modules/camera/CameraHAL.cpp
@@ -185,6 +185,7 @@
     set_callbacks         : set_callbacks,
     get_vendor_tag_ops    : get_vendor_tag_ops,
     open_legacy           : NULL,
+    set_torch_mode        : NULL,
     reserved              : {0},
 };
 } // extern "C"