usb: renesas_usbhs: Add struct device * declaration in usbhs_probe()

Since this can remove over 80 charactors in a line, this patch adds
struct device * declaration in usbhs_probe().

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>