eal: set name when creating a control thread

To avoid code duplication, add a parameter to rte_ctrl_thread_create()
to specify the name of the thread.

This requires to add a wrapper for the thread start routine in
rte_thread_init(), which will first wait that the thread is configured.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>