[hwc] add impl of HWC API

[hwc] add impl of HWC API

  add the output functions for a backend module:
     - output_hwc_window_create;
     - output_hwc_window_destroy;
     - output_hwc_validate;
     - output_hwc_get_changed_composition_types;
     - output_hwc_accept_changes;
     - output_hwc_get_target_surface_queue;
     - output_hwc_set_client_target_buffer;

  create the window functions for a backend module
     - hwc_window_get_tbm_surface_queue;
     - hwc_window_set_buffer;
     - hwc_window_set_composition_type;
     - hwc_window_set_info;
     - hwc_window_set_surface_damage;
     - hwc_window_set_zpos;
     - hwc_window_set_flags;
     - hwc_window_unset_flags;
     - hwc_window_video_get_capability;
     - hwc_window_video_get_supported_format;

Change-Id: I464fd37e5ce6e2f1548b210e935e98d3541b43cd
Signed-off-by: Roman Marchenko <r.marchenko@samsung.com>