FROMGIT: coresight: etm4x: Handle accesses to TRCSTALLCTLR

TRCSTALLCTLR register is only implemented if

   TRCIDR3.STALLCTL == 0b1

Make sure the driver touches the register only it is implemented.

Link: https://lore.kernel.org/r/20210127184617.3684379-1-suzuki.poulose@arm.com


Cc: stable@vger.kernel.org
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@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/20210201181351.1475223-32-mathieu.poirier@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit f7289606
https: //git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git next)
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Change-Id: I9f8fb2fa937246e3380f31676c67be7a76cc1d15