vboot: fix compile error with MOCK_TPM

In CL:1773088, we jumped the gun on an update to using the
context object in RollbackFwmpRead, before actually updating
the function to take vb2_context as an argument (which will
occur in CL:1728298).

BUG=b:124141368, chromium:972956
TEST=make clean && MOCK_TPM=1 make runtests
BRANCH=none

Change-Id: I0e1db6eafea169e73a806094ec6f385254fa563f
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1830238
Tested-by: Joel Kitching <kitching@chromium.org>
Tested-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Ronak Kanabar <ronak.kanabar@intel.corp-partner.google.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Julius Werner <jwerner@chromium.org>
diff --git a/firmware/lib/mocked_secdata_tpm.c b/firmware/lib/mocked_secdata_tpm.c
index 9aa0927..dc9f16c 100644
--- a/firmware/lib/mocked_secdata_tpm.c
+++ b/firmware/lib/mocked_secdata_tpm.c
@@ -33,6 +33,6 @@
 
 uint32_t RollbackFwmpRead(struct RollbackSpaceFwmp *fwmp)
 {
-	ctx->flags |= VB2_CONTEXT_NO_SECDATA_FWMP;
+	memset(fwmp, 0, sizeof(*fwmp));
 	return TPM_SUCCESS;
 }