Refactor bootblock initialisation

Makes it a bit easier to implement mainboard-specific behaviour
while executing the bootblock.

Change-Id: I04e87f89efb4fad1c0e20b62ea6a50329a286205
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/1844
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
3 files changed