nfp: flower: fix size_t compile warning

A recent addition to NFP introduced a function that formats a string with
a size_t variable. This is formatted with %ld which is fine on 64-bit
architectures but produces a compile warning on 32-bit architectures.

Fix this by using the z length modifier.

Fixes: a6156a6ab0f9 ("nfp: flower: handle merge hint messages")
Signed-off-by: John Hurley <john.hurley@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/flower/cmsg.c

@@ -217,7 +217,7 @@ nfp_flower_cmsg_merge_hint_rx(struct nfp_app *app, struct sk_buff *skb)
 	flow_cnt = msg->count + 1;
 
 	if (msg_len < struct_size(msg, flow, flow_cnt)) {
-		nfp_flower_cmsg_warn(app, "Merge hint ctrl msg too short - %d bytes but expect %ld\n",
+		nfp_flower_cmsg_warn(app, "Merge hint ctrl msg too short - %d bytes but expect %zd\n",
 				     msg_len, struct_size(msg, flow, flow_cnt));
 		return;
 	}