usb: gadget: renesas_usbhs: make sure SOF packet sending-out control

It is enabled to set SOF packet output bit when USBRST bit was set.
And USBRST bit should be set 0 when SOF packet was output.

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