flow_dissector: remove unused function flow_get_hlen declaration

commit 56193d1bce ("net: Add function for parsing the header length out
of linear ethernet frames") added this function declaration but it is
defined nowhere.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/flow_dissector.h

@@ -47,9 +47,6 @@ static inline __be32 skb_flow_get_ports(const struct sk_buff *skb,
 
 u32 flow_hash_from_keys(struct flow_keys *keys);
 
-unsigned int flow_get_hlen(const unsigned char *data, unsigned int max_len,
-			   __be16 protocol);
-
 /* struct flow_keys_digest:
  *
  * This structure is used to hold a digest of the full flow keys. This is a