mlx4: Use 'void *' as the event param of mlx4_dispatch_event()

Function mlx4_dispatch_event() takes an 'unsigned long' as its event
parameter. The actual value is none (MLX4_DEV_EVENT_CATASTROPHIC_ERROR),
a pointer to mlx4_eqe (MLX4_DEV_EVENT_PORT_MGMT_CHANGE), or a 32-bit
integer (remaining events).

In preparation to switch mlx4_en and mlx4_ib to be an auxiliary device,
the mlx4_interface.event callback is replaced with a notifier and
function mlx4_dispatch_event() gets updated to invoke
atomic_notifier_call_chain(). This requires forwarding the input 'param'
value from the former function to the latter. A problem is that the
notifier call takes 'void *' as its 'param' value, compared to
'unsigned long' used by mlx4_dispatch_event(). Re-passing the value
would need either punning it to 'void *' or passing down the address of
the input 'param'. Both approaches create a number of unnecessary casts.

Change instead the input 'param' of mlx4_dispatch_event() from
'unsigned long' to 'void *'. A mlx4_eqe pointer can be passed directly,
callers using an int value are adjusted to pass its address.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>