UPSTREAM: coresight: Properly address errors in sink::disable() functions

When disabling a sink the reference counter ensures the operation goes
through if nobody else is using it.  As such if drvdata::mode is already
set do CS_MODE_DISABLED, it is an error and should be reported as such.

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 12dfc9e022aa4e8768d127416bf841c169f8c57e).

Bug: 140266694
Change-Id: Ib9d61e50e6ded3a407ff263fef18e5dc711a7cc2
Signed-off-by: Yabin Cui <yabinc@google.com>