Patch merged into coreboot/master: vboot: provide CHIPSET_PROVIDES_VERSTAGE_MAIN_SYMBOL option

the following patch was just integrated into master:
commit 3c96e808f0bbe2957fc26bdc5e04900a8c5af58c
Author: Aaron Durbin 
Date:   Thu Oct 1 16:27:55 2015 -0500

vboot: provide CHIPSET_PROVIDES_VERSTAGE_MAIN_SYMBOL option

Certain chipsets provide their own main symbol for verstage.
    Therefore, it's necessary to know this so that those chipsets
    can leverage the common verstage flow.

BUG=chrome-os-partner:44827
    BRANCH=None
    TEST=Built nyan using this option.

Change-Id: If80784aa47b27f0ad286babcf0f42ce198b929e9
    Signed-off-by: Aaron Durbin 
    Reviewed-on: http://review.coreboot.org/11777
    Tested-by: build bot (Jenkins)
    Reviewed-by: Patrick Georgi

See http://review.coreboot.org/11777 for details.

-gerrit