spi/s3c64xx: Complain if we fail to set a transfer speed

Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/spi/spi-s3c64xx.c

@@ -957,6 +957,8 @@ static int s3c64xx_spi_setup(struct spi_device *spi)
 		if (spi->max_speed_hz >= speed) {
 			spi->max_speed_hz = speed;
 		} else {
+			dev_err(&spi->dev, "Can't set %dHz transfer speed\n",
+				spi->max_speed_hz);
 			err = -EINVAL;
 			goto setup_exit;
 		}