[nrf fromtree] drivers: ieee802154_nrf5: Fix warning in ISR prototype

The ISR prototype was changed some time ago
(6df8b39)
to (const void*) => fix the prototype used when
CONFIG_IEEE802154_NRF5_EXT_IRQ_MGMT is not set
to avoid a compile warning.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
(cherry picked from commit fb196da80912acb5db719fff48d43eaae03005c4)

drivers/ieee802154/ieee802154_nrf5.c

@@ -725,7 +725,7 @@ static int nrf5_stop(const struct device *dev)
 }
 
 #if !IS_ENABLED(CONFIG_IEEE802154_NRF5_EXT_IRQ_MGMT)
-static void nrf5_radio_irq(void *arg)
+static void nrf5_radio_irq(const void *arg)
 {
 	ARG_UNUSED(arg);