uml: after_sleep_interval should return something

I forgot to have an int-returning function actually return something.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/os-Linux/time.c

@@ -77,6 +77,7 @@ long long os_nsecs(void)
 #ifdef UML_CONFIG_NO_HZ
 static int after_sleep_interval(struct timespec *ts)
 {
+	return 0;
 }
 #else
 static inline long long timespec_to_us(const struct timespec *ts)