coresight: etm4x: Run arch feature detection on the CPU

coresight: etm4x: Run arch feature detection on the CPU

As we are about to add support for system register based devices,
we don't get an AMBA pid. So, the detection code could check
the system registers running on the CPU to check for the architecture
specific features. Thus we move the arch feature detection to
run on the CPU. We cannot always read the PID from the HW, as the
PID could be overridden by DT for broken devices. So, use the
PID from AMBA layer if available.

Link: https://lore.kernel.org/r/20210110224850.1880240-25-suzuki.poulose@arm.com
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: liuqi115@huawei.com
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210201181351.1475223-27-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>