powerpc/powernv: fix debugfs_create_dir() error checking

The debugfs_create_dir returns ERR_PTR incase of an error and the
correct way of checking it by using the IS_ERR inline function, and
not the simple null comparision. This patch fixes this.

Suggested-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Immad Mir <mirimmad17@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/CY5PR12MB64553EE96EBB3927311DB598C6459@CY5PR12MB6455.namprd12.prod.outlook.com

Author: mirimmad

arch/powerpc/platforms/powernv/opal-xscom.c

@@ -168,7 +168,7 @@ static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
 	ent->path.size = strlen((char *)ent->path.data);
 
 	dir = debugfs_create_dir(ent->name, root);
-	if (!dir) {
+	if (IS_ERR(dir)) {
 		kfree(ent->path.data);
 		kfree(ent);
 		return -1;
@@ -190,7 +190,7 @@ static int scom_debug_init(void)
 		return 0;
 
 	root = debugfs_create_dir("scom", arch_debugfs_dir);
-	if (!root)
+	if (IS_ERR(root))
 		return -1;
 
 	rc = 0;