coresight: Fixes coresight DT parse to get correct output port ID.

[ Upstream commit eeedc5421dd3b51de73e6106405c5c77f920f281 ]

Corrected to get the port numbering to allow programmable replicator driver
to operate correctly.

By convention, CoreSight devices number ports, not endpoints in
the .dts files:-

port {
     reg<N>
     endpoint {
     }
}

Existing code read endpoint number - always 0x0, rather than the correct
port number.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
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>