post code: Replaced hard-coded post code with macro

Added a macro in the post code list, which replaces hard coded
value in cpu/x86/cache/cache.c

Change-Id: I27cb27827272584a8a17a41c111e2dc155196a97
Signed-off-by: Vikram Narayanan <vikram186@gmail.com>
Reviewed-on: http://review.coreboot.org/572
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/include/console/post_codes.h

@@ -105,6 +105,13 @@
  */
 #define POST_CONSOLE_BOOT_MSG			0x40
 
+/**
+ * \brief Before enabling the cache
+ *
+ * Going to enable the cache
+ */
+#define POST_ENABLING_CACHE			0x60
+
 /**
  * \brief Devices have been enumerated
  *