i40e: handle link status change interrupt

i40e: handle link status change interrupt

As driver flag of 'RTE_PCI_DRV_INTR_LSC' was introduced
recently, it must be added in i40e. One second waiting
is needed for link up event, to wait the hardware into a
stable state, so the interrupt could be processed in two
parts. In addition, it should finally call the callback
function registered by application.

Test: http://dpdk.org/ml/archives/dev/2014-September/006091.html

Signed-off-by: Helin Zhang <helin.zhang@intel.com>
Reviewed-by: Jing Chen <jing.d.chen@intel.com>
Reviewed-by: Jijiang Liu <jijiang.liu@intel.com>
Tested-by: Min Cao <min.cao@intel.com>