LF-13425 arm64: dts: imx8mq: adjust TX drive strength of FEC

The default drive strength of TXD, TXC and TX_CTL were all set
to 0x7, which is the maximum drive strength. However, it will
cause low dB margin issue at 250MHz frequency band. Based on
the suggestion from SE team, change the drive strength from
0x7 to 0x6.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
Acked-by: Jason Liu <jason.hui.liu@nxp.com>

Author: Wei Fang

arch/arm64/boot/dts/freescale/imx8mq-evk.dts

@@ -894,18 +894,18 @@
 		fsl,pins = <
 			MX8MQ_IOMUXC_ENET_MDC_ENET1_MDC			0x3
 			MX8MQ_IOMUXC_ENET_MDIO_ENET1_MDIO		0x23
-			MX8MQ_IOMUXC_ENET_TD3_ENET1_RGMII_TD3		0x1f
-			MX8MQ_IOMUXC_ENET_TD2_ENET1_RGMII_TD2		0x1f
-			MX8MQ_IOMUXC_ENET_TD1_ENET1_RGMII_TD1		0x1f
-			MX8MQ_IOMUXC_ENET_TD0_ENET1_RGMII_TD0		0x1f
+			MX8MQ_IOMUXC_ENET_TD3_ENET1_RGMII_TD3		0x1e
+			MX8MQ_IOMUXC_ENET_TD2_ENET1_RGMII_TD2		0x1e
+			MX8MQ_IOMUXC_ENET_TD1_ENET1_RGMII_TD1		0x1e
+			MX8MQ_IOMUXC_ENET_TD0_ENET1_RGMII_TD0		0x1e
 			MX8MQ_IOMUXC_ENET_RD3_ENET1_RGMII_RD3		0x91
 			MX8MQ_IOMUXC_ENET_RD2_ENET1_RGMII_RD2		0x91
 			MX8MQ_IOMUXC_ENET_RD1_ENET1_RGMII_RD1		0x91
 			MX8MQ_IOMUXC_ENET_RD0_ENET1_RGMII_RD0		0x91
-			MX8MQ_IOMUXC_ENET_TXC_ENET1_RGMII_TXC		0x1f
+			MX8MQ_IOMUXC_ENET_TXC_ENET1_RGMII_TXC		0x1e
 			MX8MQ_IOMUXC_ENET_RXC_ENET1_RGMII_RXC		0x91
 			MX8MQ_IOMUXC_ENET_RX_CTL_ENET1_RGMII_RX_CTL	0x91
-			MX8MQ_IOMUXC_ENET_TX_CTL_ENET1_RGMII_TX_CTL	0x1f
+			MX8MQ_IOMUXC_ENET_TX_CTL_ENET1_RGMII_TX_CTL	0x1e
 			MX8MQ_IOMUXC_GPIO1_IO09_GPIO1_IO9		0x19
 		>;
 	};