The Mobiveil PCIe controller can work in either Root Complex
mode or Endpoint mode.

Introduce a new structure mobiveil_root_port and abstract the
RC related members into it so that the code can be used by both
modes.
Signed-off-by: NHou Zhiqiang <Zhiqiang.Hou@nxp.com>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: NAndrew Murray <amurray@thegoodpenguin.co.uk>