[S390] hvc_iucv: do not call iucv_unregister if iucv_register failed

If the iucv_register() functions fails, the error recovery calls
iucv_unregister() which might cause the following stack backtrace:

	(<0000000000100ab2> show_trace+0xee/0x144)
	<00000000004f1842> panic+0xb6/0x248
	<00000000001010a6> die+0x15a/0x16c
	<000000000011d936> do_no_context+0xa6/0xe4
	<00000000004f84dc> do_protection_exception+0x2e8/0x3a4
	<0000000000113afc> pgm_exit+0x0/0x14
	<00000000004e786e> iucv_unregister+0x5a/0x17c
	(<00000000004e785e> iucv_unregister+0x4a/0x17c)
	<000000000076de74> hvc_iucv_init+0x228/0x5dc
	<00000000001000c2> do_one_initcall+0x3e/0x19c
	<00000000007524a2> kernel_init+0x28e/0x404
	<0000000000105dd6> kernel_thread_starter+0x6/0xc
	<0000000000105dd0> kernel_thread_starter+0x0/0xc

Remove the call to iucv_unregister() and remove the goto label
as unregistering is the last step in the hvc_iucv initialization.
If iucv_register() fails, simply clean up hvc terminals and free
resources.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

drivers/char/hvc_iucv.c

@@ -1303,13 +1303,11 @@ static int __init hvc_iucv_init(void)
 	if (rc) {
 		pr_err("Registering IUCV handlers failed with error code=%d\n",
 			rc);
-		goto out_error_iucv;
+		goto out_error_hvc;
 	}
 
 	return 0;
 
-out_error_iucv:
-	iucv_unregister(&hvc_iucv_handler, 0);
 out_error_hvc:
 	for (i = 0; i < hvc_iucv_devices; i++)
 		if (hvc_iucv_table[i])