usb: renesas_usbhs: pop packet when urb dequeued

usbhsh_ureq_free() is not enough when urb dequeued.

Without this patch, the driver can not recognize re-connected
USB device after USB hub disconnected

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