vmwgfx: Bump major

This bumps driver major version as a result of previous incompatible
interface changes.

In addition, a leftover command definition is removed from the
vmwgfx_drm.h header.

Also a strict version check is enforced on the exebuf ioctl.

This is intended to be the last major bump before exiting staging.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>