dt-bindings: display: rk3588-dw-hdmi-qp: Add frl-enable-gpios property

dt-bindings: display: rk3588-dw-hdmi-qp: Add frl-enable-gpios property

Add an optional property to RK3588 HDMI TX Controller binding describing
a GPIO line to be asserted when operating in HDMI 2.1 FRL mode and
deasserted for HDMI 1.4/2.0 TMDS.

This is used to control an external voltage bias for HDMI data lines.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Co-developed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20251027222641.25066-2-laurent.pinchart@ideasonboard.com