vboot: Fix MOCK_SECDATA for new naming scheme

CB:37655 updated all secdata_xxx to secdata_firmware_xxx, but forgot the
code that's only compiled when MOCK_SECDATA is set. This patch fixes it.

Change-Id: Icf12fe405d7ce46345ccbdcb76f6aa1b56ed0194
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37772
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Joel Kitching <kitching@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/security/vboot/secdata_mock.c

@@ -45,7 +45,7 @@ vb2_error_t vb2ex_tpm_clear_owner(struct vb2_context *ctx)
 
 vb2_error_t antirollback_read_space_firmware(struct vb2_context *ctx)
 {
-	vb2api_secdata_create(ctx);
+	vb2api_secdata_firmware_create(ctx);
 	return VB2_SUCCESS;
 }