coresight-tpdm: Introduce TPDM subtype to TPDM driver

Introduce the new subtype of "CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM"
for TPDM components in driver.

Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/1695882586-10306-4-git-send-email-quic_taozha@quicinc.com