cbfstool: fix FIT entry checksum type value for ucode entries

commit c1072f2 [cbfstool: Update FIT entries in the second bootblock]
incorrectly changed the value of type_checksum_valid for microcode
entries from FIT_TYPE_MICROCODE to 0, breaking microcode loading on
Skylake/FSP1.1 devices (and others?).  Correct this by reverting to the
previous value.

Test: build/boot google/chell, observe FspTempRamInit no longer fails,
device boots as expected.

Change-Id: Ib2a90137c7d4acf6ecd9f06cb6f856bd7e783676
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/27266
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Naresh Solanki <naresh.solanki@intel.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/util/cbfstool/fit.c b/util/cbfstool/fit.c
index 31ab3de..ad9ab37 100644
--- a/util/cbfstool/fit.c
+++ b/util/cbfstool/fit.c
@@ -182,8 +182,7 @@
 	 * rather from the MCU header, hence we can assign zero here
 	 */
 	entry->size_reserved = 0x0000;
-	/* Checksum valid should be cleared for MCU */
-	entry->type_checksum_valid = 0;
+	entry->type_checksum_valid = FIT_TYPE_MICROCODE;
 	entry->version = FIT_MICROCODE_VERSION;
 	entry->checksum = 0;
 	fit_entry_add_size(&fit->header, sizeof(struct fit_entry));