Although the hardware supports the 64bit DMA address in design,
but later found that it actually not working.
This patch reduced the rang to 32bit.
Found-by: "Ethan" <ethanhsiao@jmicron.com> Signed-off-by: "Guo-Fu Tseng" <cooldavid@cooldavid.org> Acked-by: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>