kunit: Use ubuntu-22.04 for arm64

There's a bug in the version of qemu used by Ubuntu 24.04 that kills
the arm64 KUnit test. Revert to Ubuntu 22.04 just for that test,
until ubuntu-latest updates to qemu 9.2.0+.

Link: https://bugzilla.suse.com/show_bug.cgi?id=1236310
Signed-off-by: Phil Elwell <[email protected]>

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