include/ppsi/pp-time: fix marking timestamp as invalid

Make sure two bits are used when marking timestamp as invalid

Signed-off-by: Maciej Lipinski <maciej.lipinski@cern.ch>

include/ppsi/pp-time.h

@@ -19,6 +19,7 @@ static inline int is_incorrect(const struct pp_time *t)
 }
 static inline void mark_incorrect(struct pp_time *t)
 {
+	t->secs &= ~(0xc0LL << 56);
 	t->secs |= (0x8fLL << 56);
 }
 static inline void clear_time(struct pp_time *t)