runtime: fix the inconsistency of kq parameter of addWakeupEvent

Change-Id: I4f1668ed9085cf19c3eff17c237601a91d0660db
Reviewed-on: https://go-review.googlesource.com/c/go/+/587876
Reviewed-by: Carlos Amedee <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>

Author: panjf2000

src/runtime/netpoll_kqueue_event.go

@@ -12,7 +12,7 @@ package runtime
 // get printed somehow and they search for it.
 const kqIdent = 0xee1eb9f4
 
-func addWakeupEvent(_ int32) {
+func addWakeupEvent(kq int32) {
 	ev := keventt{
 		ident:  kqIdent,
 		filter: _EVFILT_USER,