Fix function calls in ssd1331.go

Author: ysoldak

ssd1331/ssd1331.go

@@ -152,7 +152,7 @@ func (d *Device) FillRectangle(x, y, width, height int16, c color.RGBA) error {
 		x >= d.width || (x+width) > d.width || y >= d.height || (y+height) > d.height {
 		return errors.New("rectangle coordinates outside display area")
 	}
-	d.setWindow(x, y, width, height)
+	dWindow(x, y, width, height)
 	c565 := RGBATo565(c)
 	c1 := uint8(c565 >> 8)
 	c2 := uint8(c565)
@@ -253,7 +253,7 @@ func (d *Device) Data(data uint8) {
 
 // Tx sends data to the display
 func (d *Device) Tx(data []byte, isCommand bool) {
-	d.dcPin.Set(!isCommand)
+	d.dcPin(!isCommand)
 	d.bus.Tx(data, nil)
 }