imx: add cpu type for i.MX2 and i.MX3

Add cpu types for i.MX2/3.
Signed-off-by: NPeng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: NStefano Babic <sbabic@denx.de>

arch/arm/include/asm/arch-imx/cpu.h

@@ -4,6 +4,12 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
+#define MXC_CPU_MX23		0x23
+#define MXC_CPU_MX25		0x25
+#define MXC_CPU_MX27		0x27
+#define MXC_CPU_MX28		0x28
+#define MXC_CPU_MX31		0x31
+#define MXC_CPU_MX35		0x35
 #define MXC_CPU_MX51		0x51
 #define MXC_CPU_MX53		0x53
 #define MXC_CPU_MX6SL		0x60