We need llvm-config for the target but the cross compiled target binary is
no good. We can copy the native one into the target location where it will
then return the target values though.
(From OE-Core rev: f355e55c1fcef57f288279ffb47ebeb52a72b689)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>