arm64: dts: imx8mq: Fix lcdif clocks

Add display APB and AXI clocks as required by bindings. This fixes the
warnings:
lcd-controller@30320000: clocks: [[2, 128]] is too short
        From schema: Documentation/devicetree/bindings/display/fsl,lcdif.yaml
lcd-controller@30320000: clock-names: ['pix'] is too short
        From schema: Documentation/devicetree/bindings/display/fsl,lcdif.yaml

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>