QCamera2: update for torch mode API

Bug: 2682206
Change-Id: I494f983131bb1d5273b3b7226c7e4a00586b0036
diff --git a/camera/QCamera2/QCamera2Hal.cpp b/camera/QCamera2/QCamera2Hal.cpp
index 8696f5f..6d36778 100644
--- a/camera/QCamera2/QCamera2Hal.cpp
+++ b/camera/QCamera2/QCamera2Hal.cpp
@@ -49,5 +49,6 @@
     set_callbacks: qcamera::QCamera2Factory::set_callbacks,
     get_vendor_tag_ops: qcamera::QCamera3VendorTags::get_vendor_tag_ops,
     open_legacy: qcamera::QCamera2Factory::open_legacy,
+    set_torch_mode: NULL,
     reserved: {0}
 };