net: sparx5: enable FDMA on lan969x

In a previous series, we made sure that FDMA was not initialized and
started on lan969x. Now that we are going to support it, undo that
change. In addition, make sure the chip ID check is only applicable on
Sparx5, as this is a check that is only relevant on this platform.

Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://patch.msgid.link/20250113-sparx5-lan969x-switch-driver-5-v2-1-c468f02fd623@microchip.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>