spi: omap-100k: Fix memory leak

The memory allocated for cs is not freed anywhere.
Convert to use devm_kzalloc to fix the memory leak.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/spi/spi-omap-100k.c b/drivers/spi/spi-omap-100k.c
index c9e2282..e7ffcde 100644
--- a/drivers/spi/spi-omap-100k.c
+++ b/drivers/spi/spi-omap-100k.c
@@ -283,7 +283,7 @@
 	spi100k = spi_master_get_devdata(spi->master);
 
 	if (!cs) {
-		cs = kzalloc(sizeof(*cs), GFP_KERNEL);
+		cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
 		if (!cs)
 			return -ENOMEM;
 		cs->base = spi100k->base + spi->chip_select * 0x14;