Merge branch 'udpv6_sendmsg-addr_any-fix'

Andrey Ignatov says:

====================
The patch set fixes BSD'ism in sys_sendmsg to rewrite unspecified
destination IPv6 for unconnected UDP sockets in sys_sendmsg with [::1] in
case when either CONFIG_CGROUP_BPF is enabled or when sys_sendmsg BPF hook
sets destination IPv6 to [::].

Patch 1 is the fix and provides more details.
Patch 2 adds two test cases to verify the fix.

v1->v2:
* Fix compile error in patch 1.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>