Shouldn't call AddFB2 in HWC for every commit
Cache framebuffer object into drm_fb_id_handle_cache_ (std::map<GemHandle, std::weak_ptr>),can find framebuffer from cache at next time. Unfortunately framebuffer will be closed after composition, in order to make framebuffer long-time valid, so change weak_ptr to shared_ptr.
Signed-off-by: lihh haihongx.li@intel.com