mb/asus: Get rid of device_t

Use of device_t has been abandoned in ramstage.

Change-Id: I8fe817bb514c69a647c2208a0573a2c5fe98722d
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26076
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/mainboard/asus/kgpe-d16/acpi_tables.c

@@ -26,7 +26,7 @@
 
 unsigned long acpi_fill_madt(unsigned long current)
 {
-	device_t dev;
+	struct device *dev;
 	u32 dword;
 	u32 gsi_base = 0;
 	uint32_t apicid_sp5100;