bnxt_en: Enable AER support.

Add pci_error_handler callbacks to support for pcie advanced error
recovery.

Signed-off-by: Satish Baddipadige <sbaddipa@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>