coresight: Handle errors in finding input/output ports

[ Upstream commit fe470f5f7f684ed15bc49b6183a64237547910ff ]

If we fail to find the input / output port for a LINK component
while enabling a path, we should fail gracefully rather than
assuming port "0".

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>