isdn/capi: unregister capictr notifier after init failure

capidrv_init() could leave capictr notifier dangling after init
failure.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jan Kiszka <jan.kiszka@web.de>
diff --git a/drivers/isdn/capi/capidrv.c b/drivers/isdn/capi/capidrv.c
index e54e79d..92607ed 100644
--- a/drivers/isdn/capi/capidrv.c
+++ b/drivers/isdn/capi/capidrv.c
@@ -2297,6 +2297,7 @@
 
 	errcode = capi20_get_profile(0, &profile);
 	if (errcode != CAPI_NOERROR) {
+		unregister_capictr_notifier(&capictr_nb);
 		capi20_release(&global.ap);
 		return -EIO;
 	}