net/core: fix kernel-doc warnings

Fix kernel-doc warnings in net/core:

Warning(net/core/skbuff.c:3368): No description found for parameter 'delta_truesize'
Warning(net/core/filter.c:628): No description found for parameter 'pfp'
Warning(net/core/filter.c:628): Excess function parameter 'sk' description in 'sk_unattached_filter_create'

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 016694d..d78671e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3361,7 +3361,7 @@
  * @to: prior buffer
  * @from: buffer to add
  * @fragstolen: pointer to boolean
- *
+ * @delta_truesize: how much more was allocated than was requested
  */
 bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 		      bool *fragstolen, int *delta_truesize)