ramips: mt7620: fix RGMII TXID PHY mode

the register bits for TX delay and RX delay are opposites:
when TX delay bit is set, delay is enabled
when RX delay bit is set, delay is disabled

So, when both bits are unset, it is RX delay
and when both bits are set, it is TX delay

Note: TXID is the default RGMII mode of the SOC

Fixes: 5410a8e ("ramips: mt7620: add rgmii delays support")
Signed-off-by: Michael Pratt <mcpratt@pm.me>

target/linux/ramips/files/drivers/net/ethernet/ralink/soc_mt7620.c

@@ -205,7 +205,7 @@ static void mt7620_port_init(struct fe_priv *priv, struct device_node *np)
 		break;
 	case PHY_INTERFACE_MODE_RGMII_TXID:
 		mask = 0;
-		val_delay &= ~GSW_REG_GPCx_TXDELAY;
+		val_delay |= GSW_REG_GPCx_TXDELAY;
 		val_delay |= GSW_REG_GPCx_RXDELAY;
 		break;
 	case PHY_INTERFACE_MODE_MII: