board/t102x: use fdt_setprop_string instead of fdt_setprop

Use fdt_setprop_string instead of fdt_setprop to fix string length.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/board/freescale/t102xrdb/eth_t102xrdb.c b/board/freescale/t102xrdb/eth_t102xrdb.c
index dd386bc..856ec6e 100644
--- a/board/freescale/t102xrdb/eth_t102xrdb.c
+++ b/board/freescale/t102xrdb/eth_t102xrdb.c
@@ -133,8 +133,8 @@
 	     (fm_info_get_enet_if(port) == PHY_INTERFACE_MODE_SGMII)) &&
 			(port == FM1_DTSEC3)) {
 		fdt_set_phy_handle(fdt, compat, addr, "sg_2500_aqr105_phy4");
-		fdt_setprop(fdt, offset, "phy-connection-type",
-			    "sgmii-2500", 10);
+		fdt_setprop_string(fdt, offset, "phy-connection-type",
+				   "sgmii-2500");
 		fdt_status_disabled_by_alias(fdt, "xg_aqr105_phy3");
 	}
 #endif