Support for xenpci in initramfs so we can build XEN storage driver domains with alpine
Add a new feature to mkinitfs allowing xen-pcifront.ko to be part of initramfs
PR: https://github.com/alpinelinux/mkinitfs/pull/45
(from redmine: issue id 9619, created on 2018-11-02, closed on 2019-01-23)