i40evf: support reporting PF reset

i40evf: support reporting PF reset

When Linux PF and DPDK VF are used for i40e PMD, when a PF reset occurs,
an interrupt will go via adminq event to inform the VF of the reset.
A callback mechanism is introduced for the VF to allow it to invoke a
registered callback when PF  reset happens.

Users can register a callback for this interrupt event using:
  rte_eth_dev_callback_register(portid,
		RTE_ETH_EVENT_INTR_RESET,
		reset_event_callback,
		arg);

Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
Acked-by: Helin Zhang <helin.zhang@intel.com>