imx: imx8m: add i.MX8MN variants support

Add i.MX8MN variants support

Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/include/asm/arch-imx/cpu.h b/arch/arm/include/asm/arch-imx/cpu.h
index 71f0715..b525654 100644
--- a/arch/arm/include/asm/arch-imx/cpu.h
+++ b/arch/arm/include/asm/arch-imx/cpu.h
@@ -35,6 +35,11 @@
 #define MXC_CPU_IMX8MMS		0x89 /* dummy ID */
 #define MXC_CPU_IMX8MMSL	0x8a /* dummy ID */
 #define MXC_CPU_IMX8MN		0x8b /* dummy ID */
+#define MXC_CPU_IMX8MND		0x8c /* dummy ID */
+#define MXC_CPU_IMX8MNS		0x8d /* dummy ID */
+#define MXC_CPU_IMX8MNL		0x8e /* dummy ID */
+#define MXC_CPU_IMX8MNDL		0x8f /* dummy ID */
+#define MXC_CPU_IMX8MNSL		0x181 /* dummy ID */
 #define MXC_CPU_IMX8MP		0x182/* dummy ID */
 #define MXC_CPU_IMX8QXP_A0	0x90 /* dummy ID */
 #define MXC_CPU_IMX8QM		0x91 /* dummy ID */