arm64: dts: imx8qm-apalis: Remove invalid FEC property

The 'fsl,rgmii_txc_dly' is not a valid property.

Remove it to fix the following schema warning:

imx8qm-apalis-ixora-v1.1.dtb: ethernet@5b040000: Unevaluated properties are not allowed ('fsl,rgmii_txc_dly' was unexpected)
	from schema $id: http://devicetree.org/schemas/net/fsl,fec.yaml#Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8qm-apalis.dtsi

@@ -21,7 +21,6 @@ &ethphy0 {
  * this PHY model. Use delay on MAC side instead.
  */
 &fec1 {
-	fsl,rgmii_txc_dly;
 	phy-mode = "rgmii-rxid";
 };