Using one taskqueue group with single thread to execute all admin
tasks may lead to unexpected timeouts when long running task (e.g.
handling a reset after FW update) for one interface prevents
tasks from other interfaces being executed. Taskqueue group API
doesn't let to dynamically add threads, and pre-allocating thread
for each CPU as it's done for traffic queues would be a waste
of resources on systems with small number of interfaces. Replace
global taskqueue group for admin tasks with taskqueue allocated
for each interface to allow independent execution.
Signed-off-by: Krzysztof Galazka <krzysztof.galazka@intel.com>