lxd/device/gpu_mdev: Fix mdevUUID logic
lxd/device/gpu_mdev: Fix mdevUUID logic

A recent uuid package cleanup incorrectly turned an allocation into a
definition, causing the resulting device to miss its UUID field.

Signed-off-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>

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