drm/exynos: move order to register vidi kms driver

The vidi is virtual kms driver and now it is registered earlier than
actual hw kms drivers, so it will occupy crtc index 0. Some users
assume the condition yet that actual hw kms driver has crtc index 0.
It may or may not be matter but let's arrange register order.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>