imx: mx6 add PAD_CTL_SPEED_LOW for i.MX6SX/UL

PAD_CTL_SPEED_LOW for i.MX6SX/UL is (0 << 6)

Signed-off-by: Ye.Li <B37916@freescale.com>
Signed-off-by: Peng Fan <Peng.Fan@freescale.com>

arch/arm/include/asm/imx-common/iomux-v3.h

@@ -98,7 +98,11 @@ typedef u64 iomux_v3_cfg_t;
 
 #define PAD_CTL_ODE		(1 << 11)
 
+#if defined(CONFIG_MX6SX) || defined(CONFIG_MX6UL)
+#define PAD_CTL_SPEED_LOW	(0 << 6)
+#else
 #define PAD_CTL_SPEED_LOW	(1 << 6)
+#endif
 #define PAD_CTL_SPEED_MED	(2 << 6)
 #define PAD_CTL_SPEED_HIGH	(3 << 6)