Matches what linux_agp already does and prevents gcc from throwing up:
sun_agp.c: In function 'xf86DeallocateGARTMemory':
sun_agp.c:236:40: error: cast to pointer from integer of different size
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>