replay: add missing fix for internal function

This is a fix which was missed by patch
74c0b816ad, which added current_step
parameter to the replay_advance_current_step function.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Message-Id: <156404425561.18669.13015037579222450241.stgit@pasha-Precision-3630-Tower>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

replay/replay-internal.c

@@ -229,7 +229,7 @@ void replay_mutex_unlock(void)
 
 void replay_advance_current_step(uint64_t current_step)
 {
-    int diff = (int)(replay_get_current_step() - replay_state.current_step);
+    int diff = (int)(current_step - replay_state.current_step);
 
     /* Time can only go forward */
     assert(diff >= 0);