net/bnxt: prevent device access in error state

net/bnxt: prevent device access in error state

Driver should prevent any DMA with the device when it
detects an error. When firmware is in fatal state,
stop tx/rx by assigning them to dummy functions.

Fixes: be14720def9c ("net/bnxt: support FW reset")
Fixes: 9d0cbaecc91a ("net/bnxt: support periodic FW health monitoring")
Cc: stable@dpdk.org
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>