net: use %pS for kfree_skb tracing event location

For the cases where 'reason' doesn't give any clue, it's still
nice to be able to track the kfree_skb caller location. %p doesn't
help much so let's use %pS which prints the symbol+offset.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20221123040947.1015721-1-sdf@google.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

include/trace/events/skb.h

@@ -42,7 +42,7 @@ TRACE_EVENT(kfree_skb,
 		__entry->reason = reason;
 	),
 
-	TP_printk("skbaddr=%p protocol=%u location=%p reason: %s",
+	TP_printk("skbaddr=%p protocol=%u location=%pS reason: %s",
 		  __entry->skbaddr, __entry->protocol, __entry->location,
 		  __print_symbolic(__entry->reason,
 				   DEFINE_DROP_REASON(FN, FNe)))