new helper: sigsuspend()

guts of saved_sigmask-based sigsuspend/rt_sigsuspend.  Takes
kernel sigset_t *.

Open-coded instances replaced with calling it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
index 86eb4b0..63ffac9 100644
--- a/arch/mips/kernel/signal_n32.c
+++ b/arch/mips/kernel/signal_n32.c
@@ -91,15 +91,7 @@
 	if (copy_from_user(&uset, unewset, sizeof(uset)))
 		return -EFAULT;
 	sigset_from_compat(&newset, &uset);
-	sigdelsetmask(&newset, ~_BLOCKABLE);
-
-	current->saved_sigmask = current->blocked;
-	set_current_blocked(&newset);
-
-	current->state = TASK_INTERRUPTIBLE;
-	schedule();
-	set_thread_flag(TIF_RESTORE_SIGMASK);
-	return -ERESTARTNOHAND;
+	return sigsuspend(&newset);
 }
 
 asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)