bnxt_en: Fix the PCI-AER routines

We do not support two simultaneous recoveries so check for reset
flag, BNXT_STATE_IN_FW_RESET, and do not proceed with AER further.
When the pci channel state is pci_channel_io_frozen, the PCIe link
can not be trusted so we disable the traffic immediately and stop
BAR access by calling bnxt_fw_fatal_close().  BAR access after
AER fatal error can cause an NMI.

Fixes: f75d9a0a

 ("bnxt_en: Re-write PCI BARs after PCI fatal error.")
Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>