Patch merged into coreboot/master: vboot/vbnv_flash: make I/O connection agnostic

the following patch was just integrated into master:
commit b18a6665df2633193b7863e3dd9eca230536405b
Author: Aaron Durbin 
Date:   Fri Aug 12 12:48:58 2016 -0500

vboot/vbnv_flash: make I/O connection agnostic

There's no need to be SPI specific w.r.t. how the flash is
    connected. Therefore, use the RW boot device to write the
    contents of VBNV. The erasable check was dropped because that
    information isn't available. All regions should be aligned
    accordingly on the platform for the underlying hardware
    implementation. And once the VBNV region fills the erase
    will fail.

BUG=chrome-os-partner:56151

Change-Id: I07fdc8613e0b3884e132a2f158ffeabeaa6da6ce
    Signed-off-by: Aaron Durbin 
    Reviewed-on: https://review.coreboot.org/16206
    Tested-by: build bot (Jenkins)
    Reviewed-by: Duncan Laurie 
    Reviewed-by: Paul Menzel 
    Reviewed-by: Furquan Shaikh

See https://review.coreboot.org/16206 for details.

-gerrit