net/virtio-user: move eventfd open/close into init/uninit
net/virtio-user: move eventfd open/close into init/uninit

Originally, eventfd is opened when initializing each vq; and gets closded
in virtio_user_stop_device().

To make it possible to initialize intr_handle struct in init() in following
patch, we put the open() of all eventfds into init(); and put the close()
into uninit().

Suggested-by: Yuanhan Liu <5dcef21195e64c9c08aa779bb62b25e9133eaa33@linux.intel.com>
Signed-off-by: Jianfeng Tan <4339d9ba3a87a0d192e405945005ff86667f7b0c@intel.com>
Acked-by: Yuanhan Liu <5dcef21195e64c9c08aa779bb62b25e9133eaa33@linux.intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk