x86: Add multi-processor init

Most modern x86 CPUs include more than one CPU core. The OS normally requires
that these 'Application Processors' (APs) be brought up by the boot loader.
Add the required support to U-Boot to init additional APs.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 3575d34..7c77b90 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -23,6 +23,9 @@
 
 #define X86_GDT_SIZE		(X86_GDT_NUM_ENTRIES * X86_GDT_ENTRY_SIZE)
 
+/* Length of the public header on Intel microcode blobs */
+#define UCODE_HEADER_LEN	0x30
+
 #ifndef __ASSEMBLY__
 
 /*