MFC r299518

MFC r299518

sfxge(4): update multicast filter insertion algorithm

When the multicast filters we're allowed to insert are controlled by the
hypervisor, it may be that we can insert some but not others. So we need
to have fallbacks where we insert any filters we can without rolling back
when one fails to insert.

Submitted by:   Mark Spender <mspender at solarflare.com>
Sponsored by:   Solarflare Communications, Inc.

git-svn-id: svn://svn.freebsd.org/base/stable/10@301341 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f