drm/bridge: ti-sn65dsi86: correct dsi mode_flags

Noticed while comparing register dump of how bootloader configures DSI
vs how kernel configures.  It seems the bridge still works either way,
but fixing this clears the 'CHA_DATATYPE_ERR' error status bit.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190702154419.20812-4-robdclark@gmail.com