drm/rockchip: drop use of drmP.h

Drop use of the deprecated drmP.h header file.

While touching the list of include files move the
blocks so they follow the common pattern:

\#include <linux/*>

\#include <video/*>

\#include <drm/*>

\#include ""

Within each block sort the include files.
Add the includes needed to fix build after the removal of drmP.h.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: "Heiko Stübner" <heiko@sntech.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Link: https://patchwork.freedesktop.org/patch/msgid/20190716064220.18157-19-sam@ravnborg.org