bnx2x: IGU parse error cause probe failure

If IGU parse error is encountered during the probing process, the error
propagates and the probe gracefully fails (until now, such errors were ignored,
later causing mischief).

Signed-off-by: Barak Witkowski <barak@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>