skbuff.h: fix skb_dst kernel-doc

Fix kernel-doc warnings (missing + extra entries) in skbuff.h.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

@@ -264,7 +264,7 @@ typedef unsigned char *sk_buff_data_t;
  *	@transport_header: Transport layer header
  *	@network_header: Network layer header
  *	@mac_header: Link layer header
- *	@dst: destination entry
+ *	@_skb_dst: destination entry
  *	@sp: the security path, used for xfrm
  *	@cb: Control buffer. Free for use by every layer. Put private vars here
  *	@len: Length of actual data