DM USB: xHCI: change port mapping logic for multiple hub support

To support the multiple hubs and multiple layers of hub, the
port_map_tbl should be replaced by native_ports to record all
native devices' state, including assignment state, emulation
state etc.

Tracked-On: #1434
Signed-off-by: Xiaoguang Wu <xiaoguang.wu@intel.com>
Signed-off-by: Liang Yang <liang3.yang@intel.com>
Acked-by: Yu Wang <yu1.wang@intel.com>

Author: xiaoguangwu