nb/via/vx800: Get rid of device_t

Use of device_t has been abandoned in ramstage.

Change-Id: Ib432d3c3ce2788b0138a1b0e852385ab4f9b65ee
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26425
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
3 files changed