Delete typo in SurfaceFlinger documentation

    // A layer can be attached to multiple displays when operating in mirror mode

    // A layer can be attached to multiple displays when operating in mirror mode

    // (a.k.a: when several displays are attached with equal layerStack). In this

    // (a.k.a: when several displays are attached with equal layerStack). In this

    // case we need to keep track. In non-mirror mode, a layer will have only one.

    // case we need to keep track. In non-mirror mode, a layer will have only one

    // HWCInfo. This map key is a display layerStack.

    // HWCInfo. This map key is a display layerStack.

    std::unordered_map<int32_t, HWCInfo> mHwcLayers;

    std::unordered_map<int32_t, HWCInfo> mHwcLayers;