drm/gma500: Don't busy wait on the blitter

Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
drm/gma500: Add gem wrapping of userspace pages

To be able to accelerate put_image calls we need to create gem objects
around userspace pages (wrapping). That allows us to use the blitter to
upload them. The patch introduces a new ioctl for this.

Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>