um: fix build without CONFIG_UML_TIME_TRAVEL_SUPPORT

When CONFIG_UML_TIME_TRAVEL_SUPPORT isn't set, the build was broken.
Fix this.

Fixes: 06503870 ("um: Support time travel mode")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/include/shared/timer-internal.h

@@ -54,6 +54,8 @@ static inline void time_travel_set_timer(enum time_travel_timer_mode mode,
 					 unsigned long long expiry)
 {
 }
+
+#define time_travel_timer_mode TT_TMR_DISABLED
 #endif
 
 #endif

arch/um/kernel/process.c

@@ -213,7 +213,7 @@ static void time_travel_sleep(unsigned long long duration)
 	if (time_travel_timer_mode != TT_TMR_DISABLED ||
 	    time_travel_timer_expiry < next) {
 		if (time_travel_timer_mode == TT_TMR_ONESHOT)
-			time_travel_timer_mode = TT_TMR_DISABLED;
+			time_travel_set_timer(TT_TMR_DISABLED, 0);
 		/*
 		 * time_travel_time will be adjusted in the timer
 		 * IRQ handler so it works even when the signal