drm/vmwgfx: drop use of drmP.h in header files

To facilitate removal of drmP.h in the .c
files remove the use from header files first.
Fix fallout in the other files.

Sorted include files in blocks and sorted files
within each block in alphabetical order.

This revealed a dependency from an uapi header to a header
located below drivers/gpu/drm/vmwgfx/.
Added FIXME to remind someone to fix this.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Deepak Rawat <drawat@vmware.com>
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>