Revert "nouveau/ci: temporary disable gk20a-gles"

This reverts commit 8a1a3a31da.  The farm
should be back up, and I swear nginx startup is fixed for real this time.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20775>

src/gallium/drivers/nouveau/ci/gitlab-ci.yml

@@ -41,7 +41,7 @@
     - google-nouveau-jetson-nano
 
 # 6 Jetson TK1 boards at anholt's house.
-.gk20a-gles:
+gk20a-gles:
   extends:
     - .gk20a-test
   parallel: 4