EDAC/thunderx: Check debugfs file creation retval properly

edac_debugfs_create_file() returns ERR_PTR by way of the respective
debugfs function it calls, if an error occurs.

The appropriate way to verify for errors is to use IS_ERR(). Do so.

  [ bp: Rewrite all text. ]
Signed-off-by: Yeqi Fu <asuk4.q@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230517173111.365787-1-asuk4.q@gmail.com

drivers/edac/thunderx_edac.c

@@ -481,7 +481,7 @@ static int thunderx_create_debugfs_nodes(struct dentry *parent,
 		ent = edac_debugfs_create_file(attrs[i]->name, attrs[i]->mode,
 					       parent, data, &attrs[i]->fops);
 
-		if (!ent)
+		if (IS_ERR(ent))
 			break;
 	}