darwin-user: Fix format string in debug message

This was spotted by cppcheck.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

darwin-user/signal.c

diff --git a/darwin-user/signal.c b/darwin-user/signal.c
index c530227..317ef92 100644
--- a/darwin-user/signal.c
+++ b/darwin-user/signal.c
@@ -270,8 +270,7 @@
         host_sig = target_to_host_signal(sig);
         if (host_sig != SIGSEGV && host_sig != SIGBUS) {
 #if defined(DEBUG_SIGNAL)
-    fprintf(stderr, "sigaction handler going to call sigaction\n",
-            act->sa_handler, act->sa_flags, act->sa_mask);
+            fprintf(stderr, "sigaction handler going to call sigaction\n");
 #endif
 
             sigfillset(&act1.sa_mask);