constify copy_siginfo_to_user{,32}()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index 3637e03..33cab9a 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -105,7 +105,7 @@
 }
 
 int
-copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from)
+copy_siginfo_to_user (siginfo_t __user *to, const siginfo_t *from)
 {
 	if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
 		return -EFAULT;