sensor-cache: Implement readingAssertion()

Implement readingAssertion() for cache's sensor.

Tested: Verify the sensors using `readingAssertion` have valid values in
        QEMU, e.g.

        CPU0_Status      | 0x0        | discrete   | 0x0000| na        | na        | na        | na        | na        | na

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: I3a370a48c46da244de53a3e90fbbc373cd682480
1 file changed