new helper: restore_saved_sigmask()

first fruits of ..._restore_sigmask() helpers: now we can take
boilerplate "signal didn't have a handler, clear RESTORE_SIGMASK
and restore the blocked mask from ->saved_mask" into a common
helper.  Open-coded instances switched...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/openrisc/kernel/signal.c b/arch/openrisc/kernel/signal.c
index 9ae6115..266c6fd 100644
--- a/arch/openrisc/kernel/signal.c
+++ b/arch/openrisc/kernel/signal.c
@@ -339,11 +339,7 @@
 	if (signr <= 0) {
 		/* no signal to deliver so we just put the saved sigmask
 		 * back */
-		if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
-			clear_thread_flag(TIF_RESTORE_SIGMASK);
-			sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
-		}
-
+		restore_saved_sigmask();
 	} else {		/* signr > 0 */
 		sigset_t *oldset;