usb: host: xhci-plat: omit shared hcd if either root hub has no ports

Activate the just added extension for xhci-plat and omit the shared
hcd if either of the root hubs has no ports.

Signed-off-by: Heiner Kallweit <[e-mail]>
Signed-off-by: Mathias Nyman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/xhci-plat.c

···
 
 	xhci = hcd_to_xhci(hcd);
 
+	xhci->allow_single_roothub = 1;
+
 	/*
 	 * Not all platforms have clks so it is not an error if the
 	 * clock do not exist.