encoding/xml: remove unused start parameter

Found by github.com/mvdan/unparam.

Change-Id: I5a6664cceeba1cf1c2f3236ddf4db5ce7a64b02a
Reviewed-on: https://go-review.googlesource.com/37835Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/encoding/xml/read.go

@@ -211,7 +211,7 @@ func (p *Decoder) unmarshalInterface(val Unmarshaler, start *StartElement) error
 // unmarshalTextInterface unmarshals a single XML element into val.
 // The chardata contained in the element (but not its children)
 // is passed to the text unmarshaler.
-func (p *Decoder) unmarshalTextInterface(val encoding.TextUnmarshaler, start *StartElement) error {
+func (p *Decoder) unmarshalTextInterface(val encoding.TextUnmarshaler) error {
 	var buf []byte
 	depth := 1
 	for depth > 0 {
@@ -341,13 +341,13 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 	}
 
 	if val.CanInterface() && val.Type().Implements(textUnmarshalerType) {
-		return p.unmarshalTextInterface(val.Interface().(encoding.TextUnmarshaler), start)
+		return p.unmarshalTextInterface(val.Interface().(encoding.TextUnmarshaler))
 	}
 
 	if val.CanAddr() {
 		pv := val.Addr()
 		if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) {
-			return p.unmarshalTextInterface(pv.Interface().(encoding.TextUnmarshaler), start)
+			return p.unmarshalTextInterface(pv.Interface().(encoding.TextUnmarshaler))
 		}
 	}