Remove the symlink to tests/tcg/config-*.mak, which is possible now
that unused target config files are not created either.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220929114231.583801-28-alex.bennee@linaro.org>