s390/signal: add sparse annotations

Fix the following warnings from the sparse code checker:

arch/s390/kernel/signal.c:374:38: warning: cast removes address space of expression
arch/s390/kernel/signal.c:374:65: warning: incorrect type in initializer (different address spaces)
arch/s390/kernel/signal.c:374:65:    expected unsigned short [noderef] [usertype] <asn:1>*svc
arch/s390/kernel/signal.c:374:65:    got void *

arch/s390/kernel/compat_signal.c:437:38: warning: cast removes address space of expression
arch/s390/kernel/compat_signal.c:437:65: warning: incorrect type in initializer (different address spaces)
arch/s390/kernel/compat_signal.c:437:65:    expected unsigned short [noderef] [usertype] <asn:1>*svc
arch/s390/kernel/compat_signal.c:437:65:    got void *
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/compat_signal.c

@@ -434,7 +434,7 @@ static int setup_frame32(struct ksignal *ksig, sigset_t *set,
 			ksig->ka.sa.sa_restorer | PSW32_ADDR_AMODE;
 	} else {
 		/* Signal frames without vectors registers are short ! */
-		__u16 __user *svc = (void *) frame + frame_size - 2;
+		__u16 __user *svc = (void __user *) frame + frame_size - 2;
 		if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
 			return -EFAULT;
 		restorer = (unsigned long __force) svc | PSW32_ADDR_AMODE;

arch/s390/kernel/signal.c

@@ -371,7 +371,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
 		restorer = (unsigned long) ka->sa.sa_restorer | PSW_ADDR_AMODE;
 	} else {
 		/* Signal frame without vector registers are short ! */
-		__u16 __user *svc = (void *) frame + frame_size - 2;
+		__u16 __user *svc = (void __user *) frame + frame_size - 2;
 		if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, svc))
 			return -EFAULT;
 		restorer = (unsigned long) svc | PSW_ADDR_AMODE;