ipvs: convert sched_lock to spin lock

As all read_locks are gone spin lock is preferred.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 4990de6..4a7bc63 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -734,7 +734,7 @@
 
 	/* for scheduling */
 	struct ip_vs_scheduler	*scheduler;    /* bound scheduler object */
-	rwlock_t		sched_lock;    /* lock sched_data */
+	spinlock_t		sched_lock;    /* lock sched_data */
 	void			*sched_data;   /* scheduler application data */
 
 	/* alternate persistence engine */