usb: host: xhci-plat: add platform TPL support

The TPL support is used to identify targeted devices during
EH2.0 and EH3.0 certification test, the user can add "tpl-support"
at dts to enable this feature.

Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>