CNB: netlink: add support for bulk delete / flush operations

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2193176
Tested: Only build. Will be tested by self-tests after bridge rebase.
Depends: !2472 (merged)

Commits:

12dc5c2cb7b2 ("net: rtnetlink: add msg kind names")
2e9ea3e30f69 ("net: rtnetlink: add helper to extract msg type's kind")
0569e31f1bc2 ("net: rtnetlink: use BIT for flag values")
545528d78855 ("net: netlink: add NLM_F_BULK delete request modifier")
a6cec0bcd342 ("net: rtnetlink: add bulk delete support flag")
1306d5362a59 ("net: add ndo_fdb_del_bulk")
9e83425993f3 ("net: rtnetlink: add NLM_F_BULK support to rtnl_fdb_del")
ea2c0f9e3fc2 ("net: rtnetlink: add ndm flags and state mask attributes")
5b22f62724a0 ("net: rtnetlink: fix module reference count leak issue in rtnetlink_rcv_msg")

Signed-off-by: Ivan Vecera ivecera@redhat.com