gitlab-ci: Merge "build-disabled" with "build-without-default-features"

gitlab-ci: Merge "build-disabled" with "build-without-default-features"

Both jobs are testing more or less the same thing (building QEMU with
features disabled), so we are wasting precious CI cycles here by doing
this twice. Merge the jobs by using --without-default-features by default
and just adding some additional --disable-... switches which are not
covered by the generic switch (yet). And while we're at it, also test
compilation with "--disable-fdt" (which forces us to change the list
of targets in this job, though, since some targets do not work without
fdt).

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210730143809.717079-2-thuth@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210806141015.2487502-3-alex.bennee@linaro.org>