hwc2: Teardown CWB in Create Virtual Display

Teardown CWB in Create Virtual Display. This is required to free up WB
resources if they are already reserved by readback api calls.

Change-Id: I094c3b2396efa0a4b31996252fd675ed1733e6c8
diff --git a/sdm/libs/hwc2/hwc_display.h b/sdm/libs/hwc2/hwc_display.h
index 70ac73a..3ee1551 100644
--- a/sdm/libs/hwc2/hwc_display.h
+++ b/sdm/libs/hwc2/hwc_display.h
@@ -157,6 +157,9 @@
   virtual DisplayError GetMixerResolution(uint32_t *width, uint32_t *height);
   virtual void GetPanelResolution(uint32_t *width, uint32_t *height);
   virtual std::string Dump();
+  virtual DisplayError TeardownConcurrentWriteback(void) {
+    return kErrorNotSupported;
+  }
 
   // Captures frame output in the buffer specified by output_buffer_info. The API is
   // non-blocking and the client is expected to check operation status later on.