usb: gadget: at91-udc: simplify at91rm9200_udc_pullup callback

usb: gadget: at91-udc: simplify at91rm9200_udc_pullup callback

Just simplify the use of is_on and get rid of superfluous condition.

Cc: gregkh@linuxfoundation.org
Cc: nicolas.ferre@microchip.com
Cc: alexandre.belloni@bootlin.com
Cc: linux-usb@vger.kernel.org
Cc: kernel@pengutronix.de
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20221104215516.2874922-2-m.grzeschik@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>