soc/intel/skylake: Get rid of device_t

Use of device_t has been abandoned in ramstage.

Change-Id: Idf00c029331aba30c8bfca71546cad62ff6bb0a7
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26541
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/skylake/irq.c

@@ -296,7 +296,7 @@ void soc_pch_pirq_init(const struct device *dev)
 {
 	const config_t *config = dev->chip_info;
 	uint8_t pch_interrupt_routing[MAX_PXRC_CONFIG];
-	device_t irq_dev;
+	struct device *irq_dev;
 
 	pch_interrupt_routing[0] = config->pirqa_routing;
 	pch_interrupt_routing[1] = config->pirqb_routing;