tools/memory-model: Add support for synchronize_srcu_expedited()

Given that synchronize_rcu_expedited() is supported, this commit adds
support for synchronize_srcu_expedited().
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Acked-by: Andrea Parri <andrea.parri@amarulasolutions.com>

tools/memory-model/linux-kernel.def

@@ -51,6 +51,7 @@ synchronize_rcu_expedited() { __fence{sync-rcu}; }
 srcu_read_lock(X)  __srcu{srcu-lock}(X)
 srcu_read_unlock(X,Y) { __srcu{srcu-unlock}(X,Y); }
 synchronize_srcu(X)  { __srcu{sync-srcu}(X); }
+synchronize_srcu_expedited(X)  { __srcu{sync-srcu}(X); }
 
 // Atomic
 atomic_read(X) READ_ONCE(*X)