gitlab: Move mips job to Debian 9

Support for the mips architecture has been dropped from Debian
sid. Move the mipsel job from Debian 9 to Debian sid at the same
time to keep things balanced.
Signed-off-by: NAndrea Bolognani <abologna@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

.gitlab-ci.yml

@@ -17,9 +17,9 @@ debian-9-cross-mips64el:
   <<: *job_definition
   image: quay.io/libvirt/buildenv-libvirt-debian-9-cross-mips64el:latest
 
-debian-9-cross-mipsel:
+debian-9-cross-mips:
   <<: *job_definition
-  image: quay.io/libvirt/buildenv-libvirt-debian-9-cross-mipsel:latest
+  image: quay.io/libvirt/buildenv-libvirt-debian-9-cross-mips:latest
 
 debian-10-cross-aarch64:
   <<: *job_definition
@@ -41,6 +41,6 @@ debian-sid-cross-i686:
   <<: *job_definition
   image: quay.io/libvirt/buildenv-libvirt-debian-sid-cross-i686:latest
 
-debian-sid-cross-mips:
+debian-sid-cross-mipsel:
   <<: *job_definition
-  image: quay.io/libvirt/buildenv-libvirt-debian-sid-cross-mips:latest
+  image: quay.io/libvirt/buildenv-libvirt-debian-sid-cross-mipsel:latest