arm64: dts: imx8mp-debix: remove unused fec pinctrl node

The SoM A uses the EQOS ethernet interface and not the FEC, so drop the
interface pinctrl node from the device tree.

Fixes: c86d350a ("arm64: dts: Add device tree for the Debix Model A Board")
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp-debix-model-a.dts

@@ -354,28 +354,6 @@ MX8MP_IOMUXC_SAI1_TXD6__GPIO4_IO18				0x19
 		>;
 	};
 
-	pinctrl_fec: fecgrp {
-		fsl,pins = <
-			MX8MP_IOMUXC_SAI1_RXD2__ENET1_MDC				0x3
-			MX8MP_IOMUXC_SAI1_RXD3__ENET1_MDIO				0x3
-			MX8MP_IOMUXC_SAI1_RXD4__ENET1_RGMII_RD0				0x91
-			MX8MP_IOMUXC_SAI1_RXD5__ENET1_RGMII_RD1				0x91
-			MX8MP_IOMUXC_SAI1_RXD6__ENET1_RGMII_RD2				0x91
-			MX8MP_IOMUXC_SAI1_RXD7__ENET1_RGMII_RD3				0x91
-			MX8MP_IOMUXC_SAI1_TXC__ENET1_RGMII_RXC				0x91
-			MX8MP_IOMUXC_SAI1_TXFS__ENET1_RGMII_RX_CTL			0x91
-			MX8MP_IOMUXC_SAI1_TXD0__ENET1_RGMII_TD0				0x1f
-			MX8MP_IOMUXC_SAI1_TXD1__ENET1_RGMII_TD1				0x1f
-			MX8MP_IOMUXC_SAI1_TXD2__ENET1_RGMII_TD2				0x1f
-			MX8MP_IOMUXC_SAI1_TXD3__ENET1_RGMII_TD3				0x1f
-			MX8MP_IOMUXC_SAI1_TXD4__ENET1_RGMII_TX_CTL			0x1f
-			MX8MP_IOMUXC_SAI1_TXD5__ENET1_RGMII_TXC				0x1f
-			MX8MP_IOMUXC_SAI1_RXD1__ENET1_1588_EVENT1_OUT			0x1f
-			MX8MP_IOMUXC_SAI1_RXD0__ENET1_1588_EVENT1_IN			0x1f
-			MX8MP_IOMUXC_SAI1_TXD7__GPIO4_IO19				0x19
-		>;
-	};
-
 	pinctrl_gpio_led: gpioledgrp {
 		fsl,pins = <
 			MX8MP_IOMUXC_NAND_READY_B__GPIO3_IO16				0x19