drm/exynos: Pass exynos_drm_manager in manager ops instead of dev

This patch changes the manager ops callbacks from accepting the subdrv
device pointer to taking a pointer to the manager. This will allow us
to move closer to decoupling manager/display from subdrv, and subsequently
decoupling the crtc/plane from the encoder.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>