linux-user,s390x: remove useless cast

This patch is the result of coccinelle script
scripts/coccinelle/typecast.cocci

CC: Riku Voipio <riku.voipio@iki.fi>
CC: Alexander Graf <agraf@suse.de>
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

linux-user/signal.c

@@ -4244,7 +4244,7 @@ static void setup_frame(int sig, struct target_sigaction *ka,
     env->regs[5] = 0; // FIXME: no clue... current->thread.prot_addr;
 
     /* Place signal number on stack to allow backtrace from handler.  */
-    __put_user(env->regs[2], (int *) &frame->signo);
+    __put_user(env->regs[2], &frame->signo);
     unlock_user_struct(frame, frame_addr, 1);
     return;