UPSTREAM: coresight: Properly address concurrency in sink::update() functions

When operating in CPU-wide trace scenarios and working with an N:1
source/sink HW topology, update() functions need to be made atomic
in order to avoid racing with start and stop operations.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

(Upstream commit 0916447c8728ed1ffa2bf9feee220f01d802b37e).

Bug: 140266694
Change-Id: I821793b8e9e3cebeac72741a18b90779e1c97b6b
Signed-off-by: Yabin Cui <yabinc@google.com>