cxgb3 - fix EEH

Reset the chip when the PCI link goes down.
Preserve the napi structure when a sge qset's resources are freed.
Replay only HW initialization when the chip comes out of reset.

Signed-off-by: Divy Le ray <divy@chelsio.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>