usb: host: xhci: plat: make use of new methods in xhci_plat_priv

usb: host: xhci: plat: make use of new methods in xhci_plat_priv

Now that the code has been refactored enough,
switching over to using ->plat_start() and
->init_quirk() becomes a very simple patch.

After this patch, there are no further uses for
xhci_plat_type_is() which will be removed in a
follow-up patch.

Acked-by: Yoshihiro Shimoda <[email protected]>
Signed-off-by: Felipe Balbi <[email protected]>
Signed-off-by: Mathias Nyman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>