net sched: update vlan action for batched events operations

[ Upstream commit b35475c5491a14c8ce7a5046ef7bcda8a860581a ]

Add get_fill_size() routine used to calculate the action size
when building a batch of events.

Fixes: c7e2b968 ("sched: introduce vlan action")
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>