xtensa: no need to reset handler if SA_ONESHOT

get_signal_to_deliver() already resets the signal handler if SA_ONESHOT
is set in ka->sa.sa_flags, there's no need to do it again in
handle_signal().

Furthermore, because we were modifying ka->sa.sa_handler (which is a
copy of sighand->action[]) instead of sighand->action[] the original
code actually had no effect on signal delivery.
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/xtensa/kernel/signal.c

@@ -536,9 +536,6 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset)
 		/* Set up the stack frame */
 		setup_frame(signr, &ka, &info, oldset, regs);
 
-		if (ka.sa.sa_flags & SA_ONESHOT)
-			ka.sa.sa_handler = SIG_DFL;
-
 		spin_lock_irq(&current->sighand->siglock);
 		sigorsets(&current->blocked, &current->blocked, &ka.sa.sa_mask);
 		if (!(ka.sa.sa_flags & SA_NODEFER))