usb: renesas_usbhs: remove the_controller_link

current renesas_usbhs is using new style udc_start/stop from
af1d7056
(usb: gadget: renesas: convert to new style).

with this patch we can finally remove the global "the_controller_link"

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>