drm/vc4: drop use of drmP.h

Drop use of the deprecated header drmP.h.
Fix so vc4_drv.h is now self-contained, and fixed fall-out in remaining
files.

Divided include files in blocks.
Sorted include files within their blocks.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190716064220.18157-7-sam@ravnborg.org