mlxsw: spectrum_switchdev: Don't batch VLAN operations

switchdev's VLAN object has the ability to describe a range of VLAN IDs,
but this is only used when VLAN operations are done using the SELF flag,
which is something we would like to remove as it allows one to bypass
the bridge driver.

Do VLAN operations on a per-VLAN basis, thereby simplifying the code and
preparing it for refactoring in a follow-up patchset.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>