mlxsw: core_acl_flex_keys: Split MAC and IP address flex key elements

Since in Spectrum-2, MACs are split and IP addresses are split as well,
in order to use the same elements for Spectrum and Spectrum-2 split them
now.

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