mb/msi: Get rid of device_t

Use of device_t has been abandoned in ramstage.

Change-Id: I7f29fe3b85bc56ff3f2d225822c415513e961459
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/26102
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Jonathan A. Kollasch <jakllsch@kollasch.net>
14 files changed