MINOR: quic: complete traces in qc_rx_pkt_handle()

Add missing ENTER trace for qc_rx_pkt_handle() function. LEAVE traces
are already present.

This should be backported up to 2.7.
diff --git a/src/quic_conn.c b/src/quic_conn.c
index 2095263..8bf19e7 100644
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -6335,6 +6335,8 @@
 	size_t b_cspace;
 	int io_cb_wakeup = 1;
 
+	TRACE_ENTER(QUIC_EV_CONN_LPKT, qc, pkt, NULL, qv);
+
 	if (pkt->flags & QUIC_FL_RX_PACKET_DGRAM_FIRST &&
 	    !quic_peer_validated_addr(qc) &&
 	    qc->flags & QUIC_FL_CONN_ANTI_AMPLIFICATION_REACHED) {