Continue to Kang Hammerhead video drivers, try to fix:

hardware/qcom/display/msm8974/libhwcomposer/hwc_utils.cpp: In function 'int qhwc::hwc_sync(hwc_context_t*, hwc_display_contents_1_t*, int, int)':
hardware/qcom/display/msm8974/libhwcomposer/hwc_utils.cpp:620:10: error: 'struct mdp_buf_sync' has no member named 'retire_fen_fd'
hardware/qcom/display/msm8974/libhwcomposer/hwc_utils.cpp:637:17: error: 'struct mdp_buf_sync' has no member named 'retire_fen_fd'
hardware/qcom/display/msm8974/libhwcomposer/hwc_utils.cpp:638:17: error: 'struct mdp_buf_sync' has no member named 'session_id'