dt-bindings: display: ti,am65x-dss: Re-indent the example

dt-bindings: display: ti,am65x-dss: Re-indent the example

Reduce tab size from 8 spaces to 4 spaces to make the bindings
consistent, and easy to expand.

Acked-by: "Rob Herring (Arm)" <robh@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Link: https://lore.kernel.org/r/20250528122544.817829-2-aradhya.bhatia@linux.dev
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>