As we are about to add support for sysreg access to ETM4.4+ components,
make sure that we read the registers only on the host CPU.

Link: https://lore.kernel.org/r/20210110224850.1880240-8-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/20210201181351.1475223-10-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>