Patch merged into coreboot/master: crossgcc/buildgcc: Update for recent arch additions

the following patch was just integrated into master:
commit 3e0f74d6b58e3c1e0a06e3a84923e26be36ebe1f
Author: Martin Roth 
Date:   Tue Mar 8 12:07:04 2016 -0700

crossgcc/buildgcc: Update for recent arch additions

- Add powerpc64le-linux-gnu & nds32le-elf to the instructions as
    supported architectures
    - Add nds32le-elf as a supported architecture so it will stop warning
    when you build it.

Change-Id: Ifcdbc3d082eae5b9b5f8828914e7d2b7ed1f13a4
    Signed-off-by: Martin Roth 
    Reviewed-on: https://review.coreboot.org/13961
    Tested-by: build bot (Jenkins)
    Reviewed-by: Stefan Reinauer 
    Reviewed-by: Paul Menzel

See https://review.coreboot.org/13961 for details.

-gerrit