drm/exynos/dsi: propagate info about command mode from panel

mipi_dsi framework provides information about panel's mode of work.
This info should be propagated upstream to configure all elements of
the pipeline. As CRTC is the common denominator of the pipeline we can
put such info into its structures.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>