RDMA/mlx4: Don't continue event handler after memory allocation failure

The failure to allocate memory during MLX4_DEV_EVENT_PORT_MGMT_CHANGE
event handler will cause skip the assignment logic, but
ib_dispatch_event() will be called anyway.

Fix it by calling to return instead of break after memory allocation
failure.

Fixes: 00f5ce99 ("mlx4: Use port management change event instead of smp_snoop")
Link: https://lore.kernel.org/r/12a0e83f18cfad4b5f62654f141e240d04915e10.1643622264.git.leonro@nvidia.comSigned-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx4/main.c

@@ -3237,7 +3237,7 @@ static void mlx4_ib_event(struct mlx4_dev *dev, void *ibdev_ptr,
 	case MLX4_DEV_EVENT_PORT_MGMT_CHANGE:
 		ew = kmalloc(sizeof *ew, GFP_ATOMIC);
 		if (!ew)
-			break;
+			return;
 
 		INIT_WORK(&ew->work, handle_port_mgmt_change_event);
 		memcpy(&ew->ib_eqe, eqe, sizeof *eqe);