coresight-tpdm: Add integration test support

Integration test for tpdm can help to generate the data for
verification of the topology during TPDM software bring up.

Sample:
echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink
echo 1 > /sys/bus/coresight/devices/tpdm0/enable_source
echo 1 > /sys/bus/coresight/devices/tpdm0/integration_test
echo 2 > /sys/bus/coresight/devices/tpdm0/integration_test
cat /dev/tmc_etf0 > /data/etf-tpdm0.bin

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230117145708.16739-6-quic_jinlmao@quicinc.com