drivers/xgi/z9s: Get rid of device_t

Use of device_t has been abandoned in ramstage.

Change-Id: Ia9c705d34b90ad44272a06790fbb1041029ef77d
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26069
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed