d3d11: Fix bug creating static vertex buffers

The vertex data wasn't getting properly freed, it was actually setting
the parameter itself to null for some reason.

libobs-d3d11/d3d11-subsystem.hpp

@@ -169,6 +169,8 @@ static inline D3D11_PRIMITIVE_TOPOLOGY ConvertGSTopology(gs_draw_mode mode)
 struct VBDataPtr {
 	vb_data *data;
 
+	inline void Clear() {vbdata_destroy(data); data = nullptr;}
+
 	inline VBDataPtr(vb_data *data) : data(data) {}
 	inline ~VBDataPtr() {vbdata_destroy(data);}
 };

libobs-d3d11/d3d11-vertexbuffer.cpp

@@ -136,8 +136,6 @@ gs_vertex_buffer::gs_vertex_buffer(device_t device, struct vb_data *data,
 		uvSizes.push_back(tverts->width * sizeof(float));
 	}
 
-	if (!dynamic) {
-		bfree(data);
-		data = NULL;
-	}
+	if (!dynamic)
+		vbd.Clear();
 }