pcap: Use SLL2 linktype for captures

This means we can use wireshark on our pcaps.

Signed-off-by: Rashmica Gupta <rashmica@linux.ibm.com>
Change-Id: I215af00e064d352e41d0a8eb87d5a30582998676
diff --git a/core.c b/core.c
index 5a5d247..51eda38 100644
--- a/core.c
+++ b/core.c
@@ -547,7 +547,8 @@
 		goto out;
 
 	if (mctp->capture)
-		mctp->capture(pkt, mctp->capture_data);
+		mctp->capture(pkt, MCTP_MESSAGE_CAPTURE_INCOMING,
+			      mctp->capture_data);
 
 	hdr = mctp_pktbuf_hdr(pkt);
 
@@ -681,7 +682,8 @@
 		return -1;
 
 	if (mctp->capture)
-		mctp->capture(pkt, mctp->capture_data);
+		mctp->capture(pkt, MCTP_MESSAGE_CAPTURE_OUTGOING,
+			      mctp->capture_data);
 
 	return bus->binding->tx(bus->binding, pkt);
 }