gitlab: use $MAKE instead of 'make'

gitlab: use $MAKE instead of 'make'

The lcitool generated containers have '$MAKE' set to the path
of the right 'make' binary. Using the env variable makes it
possible to override the choice per job.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240513111551.488088-3-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit c53f7a107879a2b7e719b07692a05289bf603fde)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>