zink/ci: bump the polaris10 timeout to 30 minutes

We are dangerously close to begin with, but having some failures makes
it go over the 20 minutes timeout by ~30s. Let's add 50% to be safe.

Signed-off-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31415>

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

@@ -179,9 +179,11 @@ zink-radv-polaris10-valve:
     - .radv-zink-test-valve
     - .polaris10-test-valve-kws
     - .zink-radv-manual-rules
+  timeout: 40m
   variables:
     GPU_VERSION: zink-radv-polaris10
     ZINK_DEBUG: quiet
+    B2C_TIMEOUT_OVERALL_MINUTES: 30
 
 zink-radv-navi10-valve:
   extends: