lxd/network/network/utils/sriov: Updates SRIOVGetHostDevicesInUse to use InstanceList()
lxd/network/network/utils/sriov: Updates SRIOVGetHostDevicesInUse to use InstanceList()

To avoid instantiating an Instance struct (and associated container object) when only needing to look at device and volatile config.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

hallyn/lxd,hallyn/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,atxwebs/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,atxwebs/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,hallyn/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,atxwebs/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,atxwebs/lxd