pcap: support LINKTYPE_IPV6 (229)

This is just another variant of DLT_RAW.

Ticket: #6943.
(cherry picked from commit 76322368ed)

src/decode.h

@@ -974,6 +974,7 @@ void DecodeUnregisterCounters(void);
  * Libpcap on at least OpenBSD returns 101 as datalink type for RAW pcaps though. */
 #define LINKTYPE_RAW2        101
 #define LINKTYPE_IPV4        228
+#define LINKTYPE_IPV6        229
 #define LINKTYPE_GRE_OVER_IP 778
 #define LINKTYPE_CISCO_HDLC  DLT_C_HDLC
 #define PPP_OVER_GRE         11

src/source-pcap-file-helper.c

@@ -251,6 +251,7 @@ TmEcode ValidateLinkType(int datalink, DecoderFunc *DecoderFn)
             *DecoderFn = DecodePPP;
             break;
         case LINKTYPE_IPV4:
+        case LINKTYPE_IPV6:
         case LINKTYPE_RAW:
         case LINKTYPE_RAW2:
         case LINKTYPE_GRE_OVER_IP: