net: filter: rename sk_filter_proglen -> bpf_classic_proglen

trivial rename to better match semantics of macro

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index a4216a4..57d9223 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -69,7 +69,7 @@
 		goto out;
 
 	fprog = filter->orig_prog;
-	flen = sk_filter_proglen(fprog);
+	flen = bpf_classic_proglen(fprog);
 
 	attr = nla_reserve(skb, attrtype, flen);
 	if (attr == NULL) {