kernel: bridge: multicast: backport a few more fixes for 3.10

The following patches unfortunately didn't hit the kernel stable
branches yet, therefore cherrypicking them for OpenWRT here:

* bridge: fix netfilter/NF_BR_LOCAL_OUT for own, locally generated queries
* bridge: multicast: enable snooping on general queries only
* bridge: multicast: add sanity check for general query destination

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Backport of r43841

git-svn-id: svn://svn.openwrt.org/openwrt/branches/barrier_breaker@44049 3c298f89-4303-0410-b956-a3cf2f4a3e73