MINOR: quic: Add frame addresses to QUIC_EV_CONN_PRSAFRM event traces

This should be useful to diagnose some issues.

Should be backported to 2.6.
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 0c0e719..8c44ab3 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -499,8 +499,10 @@
 			const unsigned long *val1 = a3;
 			const unsigned long *val2 = a4;
 
-			if (frm)
+			if (frm) {
+				chunk_appendf(&trace_buf, " frm@%p", frm);
 				chunk_frm_appendf(&trace_buf, frm);
+			}
 			if (val1)
 				chunk_appendf(&trace_buf, " %lu", *val1);
 			if (val2)