[PATCH] defxx: Big-endian hosts support

 The PDQ DMA engine requires a different byte-swapping mode for big-endian
hosts; also the MAC address which is read from a register through PIO has
to be byte-swapped.  These changes have been verified with DEFPA-DC (PCI)
boards and a Broadcom BCM91250A (MIPS CPU based) host.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>