SMMU_PROXY_DISPLAY_CB is used as a hint for memory driver, for special handling of secure-camera preview buffer. Add it to the MDP device as the secure-camera preview buffers will be attached with the MDP device as the dummy device. Change-Id: I439687335b29f82d9288953bd72872860af5a8a2 Signed-off-by: Veera Sundaram Sankaran <quic_veeras@quicinc.com>