spi: omap2-mcspi: Do not configure the controller on each transfer unless needed

spi_transfer->speed_hz and spi_transfer->bits_per_word used to only be set when
not using the default settings but are not set on every transfer, causing
omap2_mcspi_setup_transfer to be called on each transfer. This patch changes
the check to only call omap2_mcspi_setup_transfer if the settings needs to be
changed.
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-omap2-mcspi.c

@@ -1057,12 +1057,15 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m)
 			status = -EINVAL;
 			break;
 		}
-		if (par_override || t->speed_hz || t->bits_per_word) {
+		if (par_override ||
+		    (t->speed_hz != spi->max_speed_hz) ||
+		    (t->bits_per_word != spi->bits_per_word)) {
 			par_override = 1;
 			status = omap2_mcspi_setup_transfer(spi, t);
 			if (status < 0)
 				break;
-			if (!t->speed_hz && !t->bits_per_word)
+			if (t->speed_hz == spi->max_speed_hz &&
+			    t->bits_per_word == spi->bits_per_word)
 				par_override = 0;
 		}
 		if (cd && cd->cs_per_word) {