nfsd/sunrpc: turn enqueueing a svc_xprt into a svc_serv operation

For now, all services use svc_xprt_do_enqueue, but once we add
workqueue-based service support, we'll need to do something different.

Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Shirley Ma <shirley.ma@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --cc fs/lockd/svc.c
Simple merge

diff --cc fs/nfs/callback.c
Simple merge

diff --cc fs/nfsd/nfssvc.c
Simple merge

diff --cc include/linux/sunrpc/svc.h
Simple merge

diff --cc include/linux/sunrpc/svc_xprt.h
Simple merge

diff --cc net/sunrpc/svc_xprt.c
Simple merge