mlxsw: core: Extend port module data structures for line cards

The port module core is tasked with module operations such as setting
power mode policy and reset. The per-module information is currently
stored in one large array suited for non-modular systems where only the
main board is present (i.e., slot index 0).

As a preparation for line cards support, allocate a per line card array
according to the queried number of slots in the system. For each line
card, allocate a module array according to the queried maximum number of
modules per-slot.

Signed-off-by: Vadim Pasternak <vadimp@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>