[d3d9] Add IsDepthStencil helper to D3D9CommonTexture

src/d3d9/d3d9_common_texture.h

@@ -244,6 +244,14 @@ namespace dxvk {
       return m_desc.Usage & D3DUSAGE_RENDERTARGET;
     }
 
+    /**
+     * \brief Depth stencil
+     * \returns Whether a resource is a depth stencil or not
+     */
+    bool IsDepthStencil() const {
+      return m_desc.Usage & D3DUSAGE_DEPTHSTENCIL;
+    }
+
     /**
      * \brief Autogen Mipmap
      * \returns Whether the texture is to have automatic mip generation