The ixgb driver is using pci_alloc_consistent, thus is should also use
pci_set_consistent_dma_mask.  This allows the driver to work on SGI
systems.

In case of an error during probing it should also disable the device again.
Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>