Patch merged into coreboot/master: crossgcc: Bring back the old iasl building scheme

the following patch was just integrated into master:
commit 3df9262b096fe2284a7d91f09b7b410df0359a46
Author: Patrick Georgi 
Date:   Tue Feb 2 19:33:00 2016 +0100

crossgcc: Bring back the old iasl building scheme

This makes the cross{gcc,tools}-* targets build iasl again, without
    building it many times for cross{gcc,tools}

Change-Id: I7546c2af5f7cce3a4f1a08f593fb5cbc675d69ad
    Signed-off-by: Patrick Georgi 
    Reviewed-on: https://review.coreboot.org/13564
    Tested-by: build bot (Jenkins)
    Reviewed-by: Martin Roth

See https://review.coreboot.org/13564 for details.

-gerrit