coresight: etm4x: Detect system instructions support

commit 501c5032d2ced7b746f4e7450f31b7389e118b14 from
git@git.assembla.com:cavium/WindRiver.linux.git

ETM v4.4 onwards adds support for system instruction access
to the ETM. Detect the support on an ETM and switch to using the
mode when available.

Link: https://lore.kernel.org/r/20210110224850.1880240-23-suzuki.poulose@arm.com


Cc: Mike Leach <mike.leach@linaro.org>
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/20210201181351.1475223-25-mathieu.poirier@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ruiqiang Hao <Ruiqiang.Hao@windriver.com>