alpha: kernel: osf_sys: Set 'kts.tv_nsec' only when 'tv' has effect

The related warning:

    CC      init/do_mounts.o
  arch/alpha/kernel/osf_sys.c: In function 'SyS_osf_settimeofday':
  arch/alpha/kernel/osf_sys.c:1028:14: warning: 'kts.tv_nsec' may be used uninitialized in this function [-Wmaybe-uninitialized]
    kts.tv_nsec *= 1000;
                ^
  arch/alpha/kernel/osf_sys.c:1016:18: note: 'kts' was declared here
    struct timespec kts;
                    ^
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>

arch/alpha/kernel/osf_sys.c

@@ -1019,14 +1019,13 @@ SYSCALL_DEFINE2(osf_settimeofday, struct timeval32 __user *, tv,
  	if (tv) {
 		if (get_tv32((struct timeval *)&kts, tv))
 			return -EFAULT;
+		kts.tv_nsec *= 1000;
 	}
 	if (tz) {
 		if (copy_from_user(&ktz, tz, sizeof(*tz)))
 			return -EFAULT;
 	}
 
-	kts.tv_nsec *= 1000;
-
 	return do_sys_settimeofday(tv ? &kts : NULL, tz ? &ktz : NULL);
 }