chore: move aarch64 CPU template tests to al2023

The AL2023 Linux 6.1 kernel now has the CPU masking patches we need for
snapshot / restore to work.

Signed-off-by: Pablo Barbáchano <[email protected]>

Author: pb8o

.buildkite/pipeline_cpu_template.py

@@ -62,7 +62,7 @@ class BkStep(str, Enum):
         ],
         BkStep.LABEL: "📖 cpu templates",
         "instances": ["m6g.metal", "c7g.metal"],
-        "platforms": [("al2_armpatch", "linux_5.10")],
+        "platforms": [("al2023", "linux_6.1")],
     },
     "fingerprint": {
         BkStep.COMMAND: [