vmwgfx: Add functionality to get 3D caps

Since we don't allow user-space to map the fifo anymore,
add a parameter to get fifo hw version and
an ioctl to copy the 3D capabilities.

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