mmc: dw_mmc: add support for implementation specific callbacks

The core dw-mshc controller driver can let platform specific
implementations of the dw-mshc controller to control the hardware
as required by such implementations. This is acheived by invoking
implementation specific (optional) callbacks. Define the list of
callbacks supported the add invocation points for the same.

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 b72e4aa9..6cb043e 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -78,6 +78,8 @@
  * @data_offset: Set the offset of DATA register according to VERID.
  * @dev: Device associated with the MMC controller.
  * @pdata: Platform data associated with the MMC controller.
+ * @drv_data: Driver specific data for identified variant of the controller
+ * @priv: Implementation defined private data.
  * @biu_clk: Pointer to bus interface unit clock instance.
  * @ciu_clk: Pointer to card interface unit clock instance.
  * @slot: Slots sharing this MMC controller.
@@ -160,6 +162,8 @@
 	u16			data_offset;
 	struct device		*dev;
 	struct dw_mci_board	*pdata;
+	struct dw_mci_drv_data	*drv_data;
+	void			*priv;
 	struct clk		*biu_clk;
 	struct clk		*ciu_clk;
 	struct dw_mci_slot	*slot[MAX_MCI_SLOTS];