SeaMicro use device parameter for set_boot_device

To have consistency between the different drivers, we modify
SeaMicro to make use of the 'device' parameter instead of
'boot_device', as the other drivers are using, for the set_boot_device
vendorpassthru.

Change-Id: Id7e07924c4c028013db29566952d8dbd317a9f2c
Merge "SeaMicro use device parameter for set_boot_device"