sfc: Treat probe as unsuccessful if it scheduled a reset

From: Steve Hodgson <shodgson@solarflare.com>

efx_pci_probe_main() can return success despite a reset being scheduled.
Catch this and retry or abort probe depending on the reset type.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>