new helper: signal_delivered()

Does block_sigmask() + tracehook_signal_handler();  called when
sigframe has been successfully built.  All architectures converted
to it; block_sigmask() itself is gone now (merged into this one).

I'm still not too happy with the signature, but that's a separate
story (IMO we need a structure that would contain signal number +
siginfo + k_sigaction, so that get_signal_to_deliver() would fill one,
signal_delivered(), handle_signal() and probably setup...frame() -
take one).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/c6x/kernel/signal.c b/arch/c6x/kernel/signal.c
index eb1b308..3d8f3c2 100644
--- a/arch/c6x/kernel/signal.c
+++ b/arch/c6x/kernel/signal.c
@@ -276,8 +276,7 @@
 	/* Set up the stack frame */
 	if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
 		return;
-	block_sigmask(ka, sig);
-	tracehook_signal_handler(sig, info, ka, regs, 0);
+	signal_delivered(sig, info, ka, regs, 0);
 }
 
 /*