ARM: dts: lan966x: Enable sgpio on pcb8291

ARM: dts: lan966x: Enable sgpio on pcb8291

Enable sgpio node on pcb8291 as this is needed to be able to control
the LEDs on this board. Otherwise the LEDs support on the board will
not be available.
On the other board pcb8309 the sgpio is already enabled because it
needed to access the SFP ports.

Fixes: c47da41a5379 ("ARM: dts: lan966x: add led configuration")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20221026174303.702919-1-horatiu.vultur@microchip.com