[master] eb56e6df6 Constification (spotted by flexelint)

[Poul-Henning Kamp]

commit eb56e6df6496f98ff60b6a057aa79f7bbb920155
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Mon Aug 30 10:25:07 2021 +0000

    Constification (spotted by flexelint)

diff --git a/bin/varnishd/proxy/cache_proxy_proto.c b/bin/varnishd/proxy/cache_proxy_proto.c
index 296e0e20b..db008a230 100644
--- a/bin/varnishd/proxy/cache_proxy_proto.c
+++ b/bin/varnishd/proxy/cache_proxy_proto.c
@@ -323,7 +323,7 @@ VPX_tlv(const struct req *req, int typ, void **dst, int *len)
 }
 
 static int
-vpx_proto2(const struct worker *wrk, struct req *req)
+vpx_proto2(const struct worker *wrk, const struct req *req)
 {
 	uintptr_t *up;
 	uint16_t tlv_len;