coresight: etm4x: Handle ETM architecture version

coresight: etm4x: Handle ETM architecture version

We are about to rely on TRCDEVARCH for detecting the ETM
and its architecture version, falling back to TRCIDR1 if
the former is not implemented (in older broken implementations).

Also, we use the architecture version information to
make some decisions. Streamline the architecture version
handling by adding helpers.

Link: https://lore.kernel.org/r/20210110224850.1880240-18-suzuki.poulose@arm.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/20210201181351.1475223-20-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>