net: sparx5: add feature support

net: sparx5: add feature support

Lan969x supports a number of different features, depending on the
target. Add new field sparx5->features and initialize the features based
on the target. Also add the function sparx5_has_feature() and use it
throughout. For now, we only need to handle features: PSFP and PTP -
more will come in the future.

[1] https://www.microchip.com/en-us/product/lan9698

Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://patch.msgid.link/20241024-sparx5-lan969x-switch-driver-2-v2-15-a0b5fae88a0f@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>