Fix coreboot table size calculations.

Fix coreboot table size calculations.

The code when reporting the coreboot table size did not account
for the last added table record. This change fixes the problem.

 . rebuild coreboot, program it on the target, restart it
 . look for 'Wrote coreboot table at:' in the console log
 . observe the adequate table size reported

 $  grep 'Wrote coreboot table:' /tmp/cb.log
 Wrote coreboot table at: 00000500, 0x10 bytes, checksum c06f
 Wrote coreboot table at: 7f6fc000, 0x1a73 bytes, checksum 3e45
 $

Change-Id: Ic55501a4ae06fab2bcda9aea58e362325f2edccf
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://review.coreboot.org/703
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>