MAINTAINERS: Add unvalued folders in tests/tcg/ to the right sections

MAINTAINERS: Add unvalued folders in tests/tcg/ to the right sections

Some subfolders in tests/tcg/ are already listed in the MAINTAINERS
file, some others aren't listed yet. Add the missing ones now to the
MAINTAINERS file, too, to make sure that get_maintainers.pl reports
the correct maintainer.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>