netdevice.h: fix ndo_bridge_* comments

The argument 'flags' was missing in ndo_bridge_setlink().
ndo_bridge_dellink() was missing.

Fixes: 407af329 ("bridge: Add netlink interface to configure vlans on bridge ports")
Fixes: add511b3 ("bridge: add flags argument to ndo_bridge_setlink and ndo_bridge_dellink")
CC: Vlad Yasevich <vyasevic@redhat.com>
CC: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>