CdcEem: add NETIF_FLAG_IGMP to netif flags
CdcEem: add NETIF_FLAG_IGMP to netif flags

Marking this interface as supporting IGMP is required for mDNS.

Change-Id: Iae4adbbca12aa7bdd80297db2bc06a6d83069b00
GitOrigin-RevId: f63695e7062543ecabd8cbf4e9f3af0577eec249

google-coral/coralmicro,google-coral/coralmicro,google-coral/coralmicro,google-coral/coralmicro,google-coral/coralmicro