coresight: stm: Support marked packet

STP_PACKET_MARKED is not supported by STM currently.
Add STM_FLAG_MARKED to support marked packet in STM.

Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200916191737.4001561-3-mathieu.poirier@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>