reset: mchp: sparx5: Extend support for lan966x

This patch extends sparx5 driver to support also the lan966x. The
process to reset the switch is the same only it has different offsets.
Therefore make the driver more generic and add support for lan966x.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Steen Hegelund <steen.hegelund@microchip.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20211018091522.1113510-3-horatiu.vultur@microchip.com


Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>