SUNRPC: Remove unused svc_rqst::rq_lock field

Clean up after commit 22700f3c ("SUNRPC: Improve ordering of
transport processing").
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

include/linux/sunrpc/svc.h

@@ -311,7 +311,6 @@ struct svc_rqst {
 	struct auth_domain *	rq_gssclient;	/* "gss/"-style peer info */
 	struct svc_cacherep *	rq_cacherep;	/* cache info */
 	struct task_struct	*rq_task;	/* service thread */
-	spinlock_t		rq_lock;	/* per-request lock */
 	struct net		*rq_bc_net;	/* pointer to backchannel's
 						 * net namespace
 						 */

net/sunrpc/svc.c

@@ -638,7 +638,6 @@ svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
 		return rqstp;
 
 	__set_bit(RQ_BUSY, &rqstp->rq_flags);
-	spin_lock_init(&rqstp->rq_lock);
 	rqstp->rq_server = serv;
 	rqstp->rq_pool = pool;