constify do_coredump() argument

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 8aa507e..790d330 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -56,7 +56,7 @@
 
 /* Function parameter for binfmt->coredump */
 struct coredump_params {
-	siginfo_t *siginfo;
+	const siginfo_t *siginfo;
 	struct pt_regs *regs;
 	struct file *file;
 	unsigned long limit;