bnxt_en: log firmware debug notifications

Firmware is capable of generating asynchronous debug notifications.
The event data is opaque to the driver and is simply logged. Debug
notifications can be enabled by turning on hardware status messages
using the ethtool msglvl interface.

Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>