All the references to get_existing_state can be converted to
get_new_state or get_old_state, which means that i915 is now
get_existing_state free.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180409124656.39886-3-maarten.lankhorst@linux.intel.com
[mlankhorst: Fix alignment in prepare_plane_fb. (Ville)]
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>