nvk/ci: drop CI_TRON_TIMEOUT__BOOT_CYCLE__MINUTES

It doesn't serve any purpose when `CI_TRON_TIMEOUT__BOOT_CYCLE__RETRIES`
is not set to 1 or more.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34899>

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

@@ -207,7 +207,6 @@ zink-nvk-ga106-valve:
     - .nvk-ga106-valve
   variables:
     GPU_VERSION: zink-nvk-ga106
-    CI_TRON_TIMEOUT__BOOT_CYCLE__MINUTES: 40
     CI_TRON_TIMEOUT__OVERALL__MINUTES: 40  # usual run time: 32min
 
 zink-radv-polaris10-valve:

src/nouveau/ci/gitlab-ci.yml

@@ -9,7 +9,6 @@ nvk-ga106-vkcts-valve:
     - .nvk-valve-manual-rules
   timeout: 80m
   variables:
-    CI_TRON_TIMEOUT__BOOT_CYCLE__MINUTES: 75
     CI_TRON_TIMEOUT__OVERALL__MINUTES: 75  # usual run time: 56min
 
 nvk-ga106-vkd3d-valve:
@@ -21,7 +20,6 @@ nvk-ga106-vkd3d-valve:
   timeout: 15m
   variables:
     HWCI_TEST_SCRIPT: install/vkd3d-runner.sh
-    CI_TRON_TIMEOUT__BOOT_CYCLE__MINUTES: 10
     CI_TRON_TIMEOUT__OVERALL__MINUTES: 10  # usual run time: 5.5min
     # Random tests fail/crash when trying to run them in parallel
     FDO_CI_CONCURRENT: 1