usb: gadget: renesas_usbhs: change usbhsc_bus_ctrl() to usbsc_set_buswait()

renesas_usbhs will have register DVSTCTR control function for HOST support.
This patch changes usbhsc_bus_ctrl() to usbsc_set_buswait(),
to remove DVSTCTR access from it,

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