MINOR: quic: Potential overflow expression in qc_parse_frm()

This should fix Coverity CID 375056 where an unsigned char was used
to store a 32bit mask.
diff --git a/src/quic_frame.c b/src/quic_frame.c
index cd607ac..721b5e0 100644
--- a/src/quic_frame.c
+++ b/src/quic_frame.c
@@ -1000,8 +1000,8 @@
 struct quic_frame_builder {
 	int (*func)(unsigned char **buf, const unsigned char *end,
                  struct quic_frame *frm, struct quic_conn *conn);
+	uint32_t mask;
 	unsigned char flags;
-	unsigned char mask;
 };
 
 const struct quic_frame_builder quic_frame_builders[] = {
@@ -1041,8 +1041,8 @@
 struct quic_frame_parser {
 	int (*func)(struct quic_frame *frm, struct quic_conn *qc,
                 const unsigned char **buf, const unsigned char *end);
+	uint32_t mask;
 	unsigned char flags;
-	unsigned char mask;
 };
 
 const struct quic_frame_parser quic_frame_parsers[] = {
@@ -1100,7 +1100,7 @@
 	}
 
 	parser = &quic_frame_parsers[frm->type];
-	if (!(parser->mask & (1 << pkt->type))) {
+	if (!(parser->mask & (1U << pkt->type))) {
 		TRACE_DEVEL("unauthorized frame", QUIC_EV_CONN_PRSFRM, qc, frm);
 		return 0;
 	}
@@ -1126,10 +1126,10 @@
 	const struct quic_frame_builder *builder;
 
 	builder = &quic_frame_builders[frm->type];
-	if (!(builder->mask & (1 << pkt->type))) {
+	if (!(builder->mask & (1U << pkt->type))) {
 		/* XXX This it a bug to send an unauthorized frame with such a packet type XXX */
 		TRACE_DEVEL("frame skipped", QUIC_EV_CONN_BFRM, qc, frm);
-		BUG_ON(!(builder->mask & (1 << pkt->type)));
+		BUG_ON(!(builder->mask & (1U << pkt->type)));
 	}
 
 	if (end <= *buf) {