VBoot Reference: Add kernel rollback prevention and choosing logic.

src/platform/vboot_reference/tests/rollback_index_mock.c

Index: src/platform/vboot_reference/tests/rollback_index_mock.c
diff --git a/src/platform/vboot_reference/tests/rollback_index_mock.c b/src/platform/vboot_reference/tests/rollback_index_mock.c
index 047fb8ac05f91eb718b80d13a00ad7a96a3050e5..631721435a951c5898675e3c7d7eef0624a46560 100644
--- a/src/platform/vboot_reference/tests/rollback_index_mock.c
+++ b/src/platform/vboot_reference/tests/rollback_index_mock.c
@@ -16,7 +16,9 @@ uint16_t g_kernel_key_version = 0;
 uint16_t g_kernel_version = 0;
 
 void SetupTPM(void) {
+#ifndef NDEBUG
   fprintf(stderr, "Rollback Index Library Mock: TPM initialized.\n");
+#endif
 }
 
 uint16_t GetStoredVersion(int type) {
@@ -52,10 +54,14 @@ int WriteStoredVersion(int type, uint16_t version) {
       g_kernel_version = version;
       break;
   }
+#ifndef NDEBUG
   fprintf(stderr, "Rollback Index Library Mock: Stored Version written.\n");
+#endif
   return 1;
 }
 
 void LockStoredVersion(int type) {
+#ifndef NDEBUG
   fprintf(stderr, "Rollback Index Library Mock: Version Locked.\n");
+#endif
 }