global: replaced unused function params with _

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

conn/errors_default.go

@@ -7,6 +7,6 @@
 
 package conn
 
-func errShouldDisableUDPGSO(err error) bool {
+func errShouldDisableUDPGSO(_ error) bool {
 	return false
 }

conn/features_default.go

@@ -10,6 +10,6 @@ package conn
 
 import "net"
 
-func supportsUDPOffload(conn *net.UDPConn) (txOffload, rxOffload bool) {
+func supportsUDPOffload(_ *net.UDPConn) (txOffload, rxOffload bool) {
 	return
 }