LinuxKPI: fix pci device devres initialisation

Given we are manually setting up the "device" in PCI in some cases,
we need to initialise the list and lock for device devres here as well
as otherwise we will panic on the uninitialised lock.

Sponsored by: The FreeBSD Foundation
MFC after: 5 days
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D30681