imx: add i.MX8MM PE property

i.MX8MM does not have LVTTL, it has a PE property

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/include/asm/mach-imx/iomux-v3.h b/arch/arm/include/asm/mach-imx/iomux-v3.h
index b899a4f..720e8f7 100644
--- a/arch/arm/include/asm/mach-imx/iomux-v3.h
+++ b/arch/arm/include/asm/mach-imx/iomux-v3.h
@@ -104,7 +104,11 @@
 #define PAD_CTL_ODE		(0x1 << 5)
 #define PAD_CTL_PUE		(0x1 << 6)
 #define PAD_CTL_HYS		(0x1 << 7)
+#ifdef CONFIG_IMX8MM
+#define PAD_CTL_PE		(0x1 << 8)
+#else
 #define PAD_CTL_LVTTL		(0x1 << 8)
+#endif
 
 #elif defined CONFIG_MX7