CI: Disable Panfrost T720/T760 CI

Lab maintenance has taken down more of the infrastructure than
originally planned; also disable these until it all comes back.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6362>

.gitlab-ci/lava-gitlab-ci.yml

@@ -149,7 +149,7 @@ kernel+rootfs_armhf:
   extends:
     - .lava-test:arm64
 
-panfrost-t720-gles2:arm64:
+.panfrost-t720-gles2:arm64:
   extends:
     - .lava-test:arm64
     - .panfrost-rules
@@ -161,7 +161,7 @@ panfrost-t720-gles2:arm64:
   tags:
     - mesa-ci-aarch64-lava-collabora
 
-panfrost-t760-gles2:armhf:
+.panfrost-t760-gles2:armhf:
   extends:
     - .lava-test:armhf
     - .panfrost-rules