srcu: Unconditionally embed struct lockdep_map

Since struct lockdep_map has zero size when CONFIG_DEBUG_LOCK_ALLOC=n,
this commit removes the #ifdef from the srcu_struct structure's ->dep_map.
This change will simplify further manipulations of this field.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

include/linux/srcutree.h

@@ -82,9 +82,7 @@ struct srcu_struct {
 						/*  callback for the barrier */
 						/*  operation. */
 	struct delayed_work work;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map dep_map;
-#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 };
 
 /* Values for state variable (bottom bits of ->srcu_gp_seq). */