Make skiboot version configurable

This allows us to specify both a global default stable skiboot version
(like we've been doing up until now), or, on a per platform (or build)
basis, build a different skiboot version.

Initially, this will be used to build garrison with skiboot master
rather than with 5.1.x

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
2 files changed