cpu: imx8: show RevC instead of Rev? at boot log

Add REVC informaiton.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Frank Li <Frank.Li@nxp.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 b525654..e9c0078 100644
--- a/arch/arm/include/asm/arch-imx/cpu.h
+++ b/arch/arm/include/asm/arch-imx/cpu.h
@@ -64,6 +64,7 @@
 
 #define CHIP_REV_A		0x0
 #define CHIP_REV_B		0x1
+#define CHIP_REV_C		0x2
 
 #define BOARD_REV_1_0           0x0
 #define BOARD_REV_2_0           0x1
diff --git a/drivers/cpu/imx8_cpu.c b/drivers/cpu/imx8_cpu.c
index 85ba7b7..95c14c9 100644
--- a/drivers/cpu/imx8_cpu.c
+++ b/drivers/cpu/imx8_cpu.c
@@ -43,6 +43,8 @@
 		return "A";
 	case CHIP_REV_B:
 		return "B";
+	case CHIP_REV_C:
+		return "C";
 	default:
 		return "?";
 	}