nfp: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Edwin Peer <edwin.peer@netronome.com>
Cc: Yangtao Li <tiny.windzz@gmail.com>
Cc: Simon Horman <simon.horman@netronome.com>
Cc: oss-drivers@netronome.com
Cc: netdev@vger.kernel.org
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_debugfs.c

@@ -159,19 +159,13 @@ void nfp_net_debugfs_vnic_add(struct nfp_net *nn, struct dentry *ddir)
 	else
 		strcpy(name, "ctrl-vnic");
 	nn->debugfs_dir = debugfs_create_dir(name, ddir);
-	if (IS_ERR_OR_NULL(nn->debugfs_dir))
-		return;
 
 	/* Create queue debugging sub-tree */
 	queues = debugfs_create_dir("queue", nn->debugfs_dir);
-	if (IS_ERR_OR_NULL(queues))
-		return;
 
 	rx = debugfs_create_dir("rx", queues);
 	tx = debugfs_create_dir("tx", queues);
 	xdp = debugfs_create_dir("xdp", queues);
-	if (IS_ERR_OR_NULL(rx) || IS_ERR_OR_NULL(tx) || IS_ERR_OR_NULL(xdp))
-		return;
 
 	for (i = 0; i < min(nn->max_rx_rings, nn->max_r_vecs); i++) {
 		sprintf(name, "%d", i);
@@ -190,16 +184,7 @@ void nfp_net_debugfs_vnic_add(struct nfp_net *nn, struct dentry *ddir)
 
 struct dentry *nfp_net_debugfs_device_add(struct pci_dev *pdev)
 {
-	struct dentry *dev_dir;
-
-	if (IS_ERR_OR_NULL(nfp_dir))
-		return NULL;
-
-	dev_dir = debugfs_create_dir(pci_name(pdev), nfp_dir);
-	if (IS_ERR_OR_NULL(dev_dir))
-		return NULL;
-
-	return dev_dir;
+	return debugfs_create_dir(pci_name(pdev), nfp_dir);
 }
 
 void nfp_net_debugfs_dir_clean(struct dentry **dir)