ipv6: mcast: use min() to simplify the code

When coping sockaddr in ip6_mc_msfget(), the time of copies
depends on the minimum value between sl_count and gf_numsrc.
Using min() here is very semantic.
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240822133908.1042240-7-lizetao1@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv6/mcast.c

@@ -586,7 +586,8 @@ int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
 	const struct in6_addr *group;
 	struct ipv6_mc_socklist *pmc;
 	struct ip6_sf_socklist *psl;
-	int i, count, copycount;
+	unsigned int count;
+	int i, copycount;
 
 	group = &((struct sockaddr_in6 *)&gsf->gf_group)->sin6_addr;
 
@@ -610,7 +611,7 @@ int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
 	psl = sock_dereference(pmc->sflist, sk);
 	count = psl ? psl->sl_count : 0;
 
-	copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
+	copycount = min(count, gsf->gf_numsrc);
 	gsf->gf_numsrc = count;
 	for (i = 0; i < copycount; i++) {
 		struct sockaddr_in6 *psin6;