spi: omap2-mcspi: Fix set_cs function for active high

The core spi driver swaps the polarity of the enable based on SPI_CS_HIGH.
The omap2 controller has an internal configuration register bit called
OMAP2_MCSPI_CHCONF_EPOL to handle active high chip selects as well.

So we have to revert swap the polarity back for the correct setting of the
OMAP2_MCSPI_CHCONF_FORCE bit in omap2_mcspi_set_cs.

Signed-off-by: Michael Welling <mwelling@ieee.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 304b427..502db29 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -247,6 +247,13 @@
 {
 	u32 l;
 
+	/* The controller handles the inverted chip selects
+	 * using the OMAP2_MCSPI_CHCONF_EPOL bit so revert
+	 * the inversion from the core spi_set_cs function.
+	 */
+	if (spi->mode & SPI_CS_HIGH)
+		enable = !enable;
+
 	if (spi->controller_state) {
 		l = mcspi_cached_chconf0(spi);