v3: drop 'RTM_' prefixes, suggested by David Ahern, they
are not useful, the add/del in bridge command line is enough.
Also reword error in response to malformed/bad vlan id attribute
size.
Cc: David Ahern <dsahern@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de> Reviewed-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>