i40e: enable multicast for promiscuous mode
i40e: enable multicast for promiscuous mode

IPv6 will run NDP with multicast packets, but multicast packets will be
filtered by i40e driver by default. So we need to enable multicast when
promiscuous mode is on, or IPv6 will fail.

Signed-off-by: Ding Heng <0890068dadda1adb9d516c96bec4c9b1e705b0d4@intel.com>
Reviewed-by: Helin Zhang <aba9dfdb1a6ec8bf1ff66b95272c029f8dfde1b1@intel.com>

tsphillips/dpdk-fork,mixja/dpdk,msune/dpdk,msune/dpdk,john-mcnamara-intel/dpdk,tsphillips/dpdk-fork,mixja/dpdk,msune/dpdk,mixja/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,msune/dpdk,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,mixja/dpdk,venkynv/dpdk-mirror,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,venkynv/dpdk-mirror