drm/exynos: change callback argument of sub driver with device

[Sean Paul]

Hi Inki,
I noticed that you merged "drm/exynos: change callback argument of sub
driver with device" to your tree without posting it to me, or
dri-devel, first. I think it would have been prudent to send for
review/comments considering that:

a) we don't agree on this, and were in discussion about it last week, and
b) it essentially reverts my "Pass exynos_drm_manager in..." patch,
and changes key elements of my "Split manager/display/subdrv" patch,

Lastly, I was working on fixing the vidi errors in the patchset,
instead of just on top. For bisect reasons, this is probably
desirable.

Sean