build-setup: use `setup` instead of direct source

There is a large case statement in this script to codify the
"supported" machines and the location of their layer directory.
Much of this information is already handled by the `setup` script
found in the root of the openbmc repository.  Rather than
duplicating this information here, use the setup script directly.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: If0b3a204dd895ba965055750f1381e50e8c461e4
1 file changed