net/mlx5: Allow forwarding event type general event as is

FW general event is used by mlx5_ib for RQ delay drop timeout event
handling, in this patch we allow to forward FW general event type to mlx5
notifiers chain so mlx5_ib can handle it and to deprecate the software
version of it.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>