kobject: convert /sys/hypervisor to use kobject_create

We don't need a kset here, a simple kobject will do just fine, so
dynamically create the kobject and use it.

We also rename hypervisor_subsys to hypervisor_kset to catch all users
of the variable.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

arch/s390/hypfs/inode.c

@@ -506,7 +506,7 @@ static int __init hypfs_init(void)
 			goto fail_diag;
 		}
 	}
-	s390_subsys.kobj.kset = &hypervisor_subsys;
+	s390_subsys.kobj.parent = hypervisor_kobj;
 	rc = subsystem_register(&s390_subsys);
 	if (rc)
 		goto fail_sysfs;