mlxsw: spectrum_acl: Move block helpers into inline header functions

The struct is defined in the header, no need to have the helpers
in the c file. Move the helpers to the header.

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>