tests/: Add CMocka unit-test infrastructure

This adds the CMocka unit-testing infrastructure into
the meson build system which we will latter follow up
with unit-tests for flashrom's core logic.

BUG=b:157280555
BRANCH=none
TEST=builds

Change-Id: I66665f56627b3d99049176bfbebbd771b080370a
Signed-off-by: Edward O'Callaghan <quasisec@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/41622
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

tests/tests.c

@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* This file is part of the coreboot project. */
+
+#include <include/test.h>
+#include "tests.h"
+
+#include <stdio.h>
+
+/* redefinitions/wrapping */
+void __wrap_physunmap(void *virt_addr, size_t len)
+{
+	fprintf(stderr, "%s\n", __func__);
+}
+void *__wrap_physmap(const char *descr, uintptr_t phys_addr, size_t len)
+{
+	fprintf(stderr, "%s\n", __func__);
+	return NULL;
+}
+
+int main(void)
+{
+	int ret = 0;
+
+	return ret;
+}