We need consistent configuration files for opkg so we might as well always use
the full list. This is equal to PACKAGE_ARCHS in the non-multilib case.
This fixes various multilib failures with ipk multilibs.
(From OE-Core rev: bc85abc5013d0c831cc3c3823df45536c293aaba)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>