mmc: dw_mmc: add support for exynos specific implementation of dw-mshc

Samsung Exynos SoC's extend the dw-mshc controller for additional clock
and bus control. Add support for these extensions and include provide
device tree based discovery suppory as well.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index 6cb043e..7c6a113 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -227,7 +227,7 @@
 	u32 num_slots;
 
 	u32 quirks; /* Workaround / Quirk flags */
-	unsigned int bus_hz; /* Bus speed */
+	unsigned int bus_hz; /* Clock speed at the cclk_in pad */
 
 	unsigned int caps;	/* Capabilities */
 	unsigned int caps2;	/* More capabilities */