infiniband: i40iw: Replace GFP_ATOMIC with GFP_KERNEL in i40iw_make_listen_node

i40iw_make_listen_node() is never called in atomic context.

i40iw_make_listen_node() is only called by i40iw_create_listen, which is
set as ".create_listen" in struct iw_cm_verbs.

Despite never getting called from atomic context,
i40iw_make_listen_node() calls kzalloc() with GFP_ATOMIC,
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
which can sleep and improve the possibility of sucessful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/i40iw/i40iw_cm.c

@@ -2872,7 +2872,7 @@ static struct i40iw_cm_listener *i40iw_make_listen_node(
 
 	if (!listener) {
 		/* create a CM listen node (1/2 node to compare incoming traffic to) */
-		listener = kzalloc(sizeof(*listener), GFP_ATOMIC);
+		listener = kzalloc(sizeof(*listener), GFP_KERNEL);
 		if (!listener)
 			return NULL;
 		cm_core->stats_listen_nodes_created++;