phy: sparx5-serdes: add support for branching on chip type

In preparation for lan969x, add a way to branch out on code that is to
be executed on either Sparx5 or lan969x.  Initially, this is required to
branch out when checking the SERDES types and SERDES speeds, since the
handling of these differ on the two platforms. This will also be used by
the lan969x driver introduced in a subsequent patch.

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-v2-7-d695bcb57b84@microchip.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>