usb: xhci: plat: add ->plat_start() and ->init_quirk() methods

these two methods will be used to hide
platform-specific details so we can get rid of
xhci_plat_type_is() in a later patch.

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

drivers/usb/host/xhci-plat.h

···
 struct xhci_plat_priv {
 	enum xhci_plat_type type;
 	const char *firmware_name;
+	void (*plat_start)(struct usb_hcd *);
+	int (*init_quirk)(struct usb_hcd *);
 };
 
 #define hcd_to_xhci_priv(h) ((struct xhci_plat_priv *)hcd_to_xhci(h)->priv)