struct mipi_dsi_msg is a read-only structure, drivers should never need
to modify it. Make this explicit by making all references to the struct
const.
Acked-by: NAndrzej Hajda <a.hajda@samsung.com>
Reviewed-by: NSean Paul <seanpaul@chromium.org>
Signed-off-by: NThierry Reding <treding@nvidia.com>