powerpc: T2081QDS: Remove macro T2081QDS

Use TARGET_T2081QDS from Kconfig instead.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/board/freescale/t208xqds/t208xqds.c b/board/freescale/t208xqds/t208xqds.c
index e307ccb..26093ea 100644
--- a/board/freescale/t208xqds/t208xqds.c
+++ b/board/freescale/t208xqds/t208xqds.c
@@ -191,7 +191,7 @@
 		 */
 		 QIXIS_WRITE(brdcfg[12], 0x1a);
 		 break;
-#elif defined(CONFIG_T2081QDS)
+#elif defined(CONFIG_TARGET_T2081QDS)
 	case 0x50:
 	case 0x51:
 		/* SD1(A:D) => SLOT2 XAUI