cnic: Fix big endian bug

The chip's page tables did not set up properly on big endian machines,
causing EEH errors on PPC machines.

Reported-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>