imx: mx27 implement get_cpu_rev

Implement get_cpu_rev to support runtime check using is_cpu_type.
Signed-off-by: NPeng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: NStefano Babic <sbabic@denx.de>

arch/arm/cpu/arm926ejs/mx27/generic.c

@@ -12,6 +12,7 @@
 #include <asm/arch/imx-regs.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/gpio.h>
+#include <asm/imx-common/sys_proto.h>
 #ifdef CONFIG_MXC_MMC
 #include <asm/arch/mxcmmc.h>
 #endif
@@ -159,6 +160,11 @@ unsigned int mxc_get_clock(enum mxc_clock clk)
 }
 
 
+u32 get_cpu_rev(void)
+{
+	return MXC_CPU_MX27 << 12;
+}
+
 #if defined(CONFIG_DISPLAY_CPUINFO)
 int print_cpuinfo (void)
 {