uml-utilities: Fix build errors exposed with multilib

With multilib it cant package the files that go into
the arch independend lib dir

Fixes

ERROR: QA Issue: uml-utilities: Files/directories were installed but not
shipped
  /usr/lib
  /usr/lib/uml
  /usr/lib/uml/port-helper
  /usr/lib/uml/.debug
  /usr/lib/uml/.debug/port-helper

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>