tests/tcg/multiarch: Build fix for linux-test

tests/tcg/multiarch: Build fix for linux-test

To keep the compiler happy, and to fit in our buildsys flags:

- Make local functions "static"
- #ifdef out unused functions
- drop cutils/osdep dependencies

Signed-off-by: Fam Zheng <famz@redhat.com>
[AJB: drop cutils/osdep dependencies]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>