The cycle64 sample is intended to complement
`test_clock_cycle_64()` in `tests/kernel/common`.
The sample demonstrates the upper 32-bits of the 64-bit cycle
counter incrementing when the bottom 32-bits roll over from
`UINT32_MAX` to 0.
If the upper 32-bits of the 64-bit cycle counter does not
increment, then an error message is printed.
```
west build -p auto -b qemu_cortex_a53 -t run \
samples/kernel/cycle64
...
*** Booting Zephyr OS build v2.7.99-1124-gd7ba4e394832 ***
wrap-around should occur in 68s
[ddd:hh:mm:ss.0ms]
[000:00:00:00.020]: c64: 0000000000174258
[000:00:01:08.760]: c64: 000000010027f8bb
[000:00:02:17.490]: c64: 0000000200348c85
```
Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
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