driver/net/fm/memac_phy: set NEG bit for external MDIOs

NEG bit default is '1' for external MDIOs as per FMAN-v3 RM, but on some
platforms, e.g. T2080QDS, this bit is '0', which leads to MDIO failure
on XAUI PHY, so set this bit definitely to align with the RM.

Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/drivers/net/fm/memac_phy.c b/drivers/net/fm/memac_phy.c
index e432ae7..a155d89 100644
--- a/drivers/net/fm/memac_phy.c
+++ b/drivers/net/fm/memac_phy.c
@@ -139,9 +139,12 @@
 	 * is zero, so MDIO clock is disabled.
 	 * So, for proper functioning of MDIO, MDIO_CLK_DIV bits needs to
 	 * be properly initialized.
+	 * NEG bit default should be '1' as per FMAN-v3 RM, but on platform
+	 * like T2080QDS, this bit default is '0', which leads to MDIO failure
+	 * on XAUI PHY, so set this bit definitely.
 	 */
 	setbits_be32(&((struct memac_mdio_controller *)info->regs)->mdio_stat,
-		     MDIO_STAT_CLKDIV(258));
+		     MDIO_STAT_CLKDIV(258) | MDIO_STAT_NEG);
 
 	return mdio_register(bus);
 }