packet: Add PACKET_COPY_THRESH into dump/restore

No test for it, sorry :( There's no easy way to check it works.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

protobuf/packet-sock.proto

@@ -18,4 +18,5 @@ message packet_sock_entry {
 	required bool		vnet_hdr	= 12;
 	required bool		loss		= 13;
 	required uint32		timestamp	= 14;
+	required uint32		copy_thresh	= 15;
 }

sk-packet.c

@@ -61,6 +61,7 @@ static int dump_one_packet_fd(int lfd, u32 id, const struct fd_parms *p)
 	psk.version = sd->nli.pdi_version;
 	psk.reserve = sd->nli.pdi_reserve;
 	psk.timestamp = sd->nli.pdi_tstamp;
+	psk.copy_thresh = sd->nli.pdi_copy_thresh;
 	psk.aux_data = (sd->nli.pdi_flags & PDI_AUXDATA ? true : false);
 	psk.orig_dev = (sd->nli.pdi_flags & PDI_ORIGDEV ? true : false);
 	psk.vnet_hdr = (sd->nli.pdi_flags & PDI_VNETHDR ? true : false);
@@ -142,6 +143,9 @@ static int open_packet_sk(struct file_desc *d)
 	if (restore_opt(sk, SOL_PACKET, PACKET_TIMESTAMP, &pse->timestamp))
 		goto err_cl;
 
+	if (restore_opt(sk, SOL_PACKET, PACKET_COPY_THRESH, &pse->copy_thresh))
+		goto err_cl;
+
 	if (pse->aux_data) {
 		yes = 1;
 		if (restore_opt(sk, SOL_PACKET, PACKET_AUXDATA, &yes))