mtd: gpmi: add gpmi support for imx6sx

The gpmi's IP for imx6sx is nearly the same as the gpmi's IP for imx6q,
except the following two new features:

     (1) the new BCH contoller has 62-BIT correcting ECC strength
            (The BCH for imx6q only has 40-BIT ECC strength).

     (2) add the hardware Randomizer support.

This patch does the follow changes:

     (1) add a new macro GPMI_IS_MX6SX to represent the imx6sx's gpmi.

     (2) add a new macro GPMI_IS_MX6.
           We use this macro to initialize the same registers for both
         imx6sx and imx6q, and so on.

     (3) add a new gpmi_devdata instance, the gpmi_devdata_imx6sx, for
         imx6sx.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
index 7904e83..32c6ba4 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
@@ -122,7 +122,8 @@
 enum gpmi_type {
 	IS_MX23,
 	IS_MX28,
-	IS_MX6Q
+	IS_MX6Q,
+	IS_MX6SX
 };
 
 struct gpmi_devdata {
@@ -298,4 +299,7 @@
 #define GPMI_IS_MX23(x)		((x)->devdata->type == IS_MX23)
 #define GPMI_IS_MX28(x)		((x)->devdata->type == IS_MX28)
 #define GPMI_IS_MX6Q(x)		((x)->devdata->type == IS_MX6Q)
+#define GPMI_IS_MX6SX(x)	((x)->devdata->type == IS_MX6SX)
+
+#define GPMI_IS_MX6(x)		(GPMI_IS_MX6Q(x) || GPMI_IS_MX6SX(x))
 #endif