imx: cpu: add CHIP_REV_2_1 macro

Introduce CHIP_REV_2_1 macro.

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 2af7965..46431b7 100644
--- a/arch/arm/include/asm/arch-imx/cpu.h
+++ b/arch/arm/include/asm/arch-imx/cpu.h
@@ -41,6 +41,7 @@
 #define CHIP_REV_1_2            0x12
 #define CHIP_REV_1_5            0x15
 #define CHIP_REV_2_0            0x20
+#define CHIP_REV_2_1            0x21
 #define CHIP_REV_2_5            0x25
 #define CHIP_REV_3_0            0x30