Turn on fboRenderMipmap for D3D11

src/libANGLE/renderer/d3d/d3d11/renderer11_utils.cpp

@@ -1628,7 +1628,7 @@ void GenerateCaps(ID3D11Device *device,
     extensions->textureUsage       = true;  // This could be false since it has no effect in D3D11
     extensions->discardFramebuffer = true;
     extensions->translatedShaderSource           = true;
-    extensions->fboRenderMipmap                  = false;
+    extensions->fboRenderMipmap                  = true;
     extensions->debugMarker                      = true;
     extensions->eglImage                         = true;
     extensions->eglImageExternal                 = true;