radeon_gart_fini might call GART unbind callback function which
might try to access GART table but if gart_disable is call first
the GART table will be unmapped so any access to it will oops.
Signed-off-by: NJerome Glisse <jglisse@redhat.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>