Added struct members for bootloader offset/size.
Added struct members for bootloader offset/size.

Review URL: http://codereview.chromium.org/2163003

coreboot/vboot,coreboot/vboot,ccaapton/vboot_reference,ionave/seismograph,acorn-marvell/vboot_reference,marineam/seismograph,marineam/seismograph,acorn-marvell/vboot_reference,marineam/seismograph,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,acorn-marvell/vboot_reference,coreboot/vboot,ccaapton/vboot_reference,ccaapton/vboot_reference,ccaapton/vboot_reference,ionave/seismograph,ionave/seismograph,geekboxzone/mmallow_external_vboot_reference,acorn-marvell/vboot_reference,marineam/seismograph,coreboot/vboot,geekboxzone/mmallow_external_vboot_reference,geekboxzone/mmallow_external_vboot_reference,coreboot/vboot