[S390] Get rid of a lot of sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index 861888a..8d17b2a 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -275,8 +275,8 @@
 	}
 
 	set_fs (KERNEL_DS);
-	ret = do_sigaltstack((stack_t __user *) (uss ? &kss : NULL),
-			     (stack_t __user *) (uoss ? &koss : NULL),
+	ret = do_sigaltstack((stack_t __force __user *) (uss ? &kss : NULL),
+			     (stack_t __force __user *) (uoss ? &koss : NULL),
 			     regs->gprs[15]);
 	set_fs (old_fs);
 
@@ -401,7 +401,7 @@
 		goto badframe; 
 
 	set_fs (KERNEL_DS);
-	do_sigaltstack((stack_t __user *)&st, NULL, regs->gprs[15]);
+	do_sigaltstack((stack_t __force __user *)&st, NULL, regs->gprs[15]);
 	set_fs (old_fs);
 
 	return regs->gprs[2];