SUNRPC: service request network namespace helper introduced

This is a cleanup patch - makes code looks simplier.
It replaces widely used rqstp->rq_xprt->xpt_net by introduced SVC_NET(rqstp).

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index e64b01d..742ff4f 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -863,7 +863,7 @@
 		.drc_status = 0,
 		.clp = NULL,
 		.slotid = NFS4_NO_SLOT,
-		.net = rqstp->rq_xprt->xpt_net,
+		.net = SVC_NET(rqstp),
 	};
 	unsigned int nops = 0;
 
@@ -879,7 +879,7 @@
 		return rpc_garbage_args;
 
 	if (hdr_arg.minorversion == 0) {
-		cps.clp = nfs4_find_client_ident(rqstp->rq_xprt->xpt_net, hdr_arg.cb_ident);
+		cps.clp = nfs4_find_client_ident(SVC_NET(rqstp), hdr_arg.cb_ident);
 		if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
 			return rpc_drop_reply;
 	}