vhost: get rid of linked list for devices
vhost: get rid of linked list for devices

While we use a single linked list to maintain all devices, we could
use a static array to achieve the same goal, just like what we did
to maintain the eth devices with rte_eth_devices array. This could
simplifies the code a bit.

Signed-off-by: Yuanhan Liu <5dcef21195e64c9c08aa779bb62b25e9133eaa33@linux.intel.com>
Acked-by: Huawei Xie <3b3be4428106761300a2ee559c9f71ecdb091553@intel.com>

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