The "drvdata->atclk" clock is optional, but if it gets set to an error
pointer then we're accidentally return an uninitialized variable instead
of success.

Fixes: 78e6427b ("coresight: funnel: Support static funnel")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20190620221237.3536-6-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>