drm/fb-helper: Set plane rotation directly

The point behind standardizing properties into core drm state
structures is also that internal code looks prettiers. Take advantage
of that and set rotation directly in the fbdev atomic code.

Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1445012594-25988-1-git-send-email-daniel.vetter@ffwll.ch


Acked-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>