kunit: Try ubuntu-22.04 for arm64

Author: pelwell

.github/workflows/kunit.yml

@@ -40,7 +40,7 @@ jobs:
 
   vc4-arm64:
     name: VC4 Unit Tests on ARM64
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     steps:
       - uses: actions/checkout@v4