mlxsw: i2c: Extend initialization by querying resources data

Extend initialization flow by query requests for chip resources data in
order to obtain chip's specific capabilities, like the number of ports.

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