llvmpipe/ci: bump timeout for nightly job to 1h

Looking at recent jobs, the runtime has increased to ~40min, but since
it runs on a shared runner with other jobs at the same time, it can
randomly take much longer, and it has reached 45 minutes several times,
so bump up the timeout to leave enough margin.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30424>

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

@@ -41,7 +41,7 @@ llvmpipe-full:
   extends:
     - llvmpipe
     - .llvmpipe-manual-rules
-  timeout: 45m  # base runtime = 30m
+  timeout: 1h  # base runtime = 40m
   variables:
     DEQP_FRACTION: 1