[mDNS] Support interface names larger than 8 characters

Interface names >8 character would cause the IPv6 interface
enumeration for mDNS to fail. None of those interfaces would
get mDNS packets.

(cherry-pick of commit db3e830f3f3dbc8e4d545785db4ed01e3e1cc382)

Bug: 30101764
Change-Id: I761422e53d787c7e50866c1bc87eb5d2a4e95b0e
1 file changed