selfboot: cleanup

selfboot: cleanup

- move cbfs_load_payload to the end so we can drop the prototype
- move lb_start and lb_end to the beginning so they can be used
  in other functions.
- drop two unused function declarations
- break a 80+ characters line
- fix a comment

Change-Id: I460aa1e2ccf9d95ac12233af001076f73ab0268e
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/424
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>