phy: sparx5-serdes: add constants to match data

phy: sparx5-serdes: add constants to match data

We need to handle a few different constants that differ for Sparx5 and
lan969x. Add a new struct: sparx5_serdes_consts for this purpose. We
populate it with an initial field for the number of SERDES'es: sd_max.

Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Link: https://lore.kernel.org/r/20240909-sparx5-lan969x-serdes-driver-v2-2-d695bcb57b84@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>