wintun: Simplify Read method()

Signed-off-by: Simon Rozman <simon@rozman.si>

tun/tun_windows.go

@@ -203,8 +203,9 @@ func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
 	select {
 	case err := <-tun.errors:
 		return 0, err
-
 	default:
+	}
+
 	for {
 		if tun.rdNextPacket < tun.rdBuff.numPackets {
 			// Get packet from the queue.
@@ -262,7 +263,6 @@ func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
 			continue
 		}
 	}
-	}
 }
 
 // Note: flush() and putTunPacket() assume the caller comes only from a single thread; there's no locking.