vxlan: make netlink notify in vxlan_fdb_destroy optional

[ Upstream commit f6e053858671bb156b6e44ad66418acc8c7f4e77 ]

Add a new option do_notify to vxlan_fdb_destroy to make
sending netlink notify optional. Used by a later patch.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>