net: fman: fix 2.5G SGMII settings

The settings for 2.5G SGMII are wrong, which the 2.5G case is missed in
set_if_mode(), and the serdes PCS configuration are wrong, this patch uses
the correct settings took from Linux.

Signed-off-by: Shaohui Xie <Shaohui.Xie@nxp.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/include/fsl_memac.h b/include/fsl_memac.h
index bed2a40..431c2a0 100644
--- a/include/fsl_memac.h
+++ b/include/fsl_memac.h
@@ -226,6 +226,7 @@
 #define PHY_SGMII_CR_PHY_RESET      0x8000
 #define PHY_SGMII_CR_RESET_AN       0x0200
 #define PHY_SGMII_CR_DEF_VAL        0x1140
+#define PHY_SGMII_IF_SPEED_GIGABIT  0x0008
 #define PHY_SGMII_DEV_ABILITY_SGMII 0x4001
 #define PHY_SGMII_IF_MODE_AN        0x0002
 #define PHY_SGMII_IF_MODE_SGMII     0x0001