VBoot Reference: Add version checking to for preventing rollbacks.

src/platform/vboot_reference/include/utility.h

Index: src/platform/vboot_reference/include/utility.h
diff --git a/src/platform/vboot_reference/include/utility.h b/src/platform/vboot_reference/include/utility.h
index 5dc6d2838951c627af4ffc15b76672435d39439f..79713477c882e71b5d3735de37a6eba70fab16d1 100644
--- a/src/platform/vboot_reference/include/utility.h
+++ b/src/platform/vboot_reference/include/utility.h
@@ -13,6 +13,14 @@
 #include <inttypes.h>
 #include <string.h>
 
+/* Combine [msw] and [lsw] uint16s to a uint32_t with its [msw] and
+ * [lsw] forming the most and least signficant 16-bit words.
+ */
+#define CombineUint16Pair(msw,lsw) (((msw) << 16) |     \
+                                    (((lsw)) & 0xFFFF))
+/* Return the minimum of (a) or (b). */
+#define Min(a, b) (((a) < (b)) ? (a) : (b))
+
 /* Allocate [size] bytes and return a pointer to the allocated memory. Abort
  * on error.
  */