cosmetic: delete misleading comment /* CONFIG_BOARDDIR */

CONFIG_BOARDDIR is not referenced in these linker scripts.
The comment /* CONFIG_BOARDDIR */ is misleading.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/arch/powerpc/cpu/mpc85xx/u-boot-nand.lds b/arch/powerpc/cpu/mpc85xx/u-boot-nand.lds
index d77a6dc..f933b21 100644
--- a/arch/powerpc/cpu/mpc85xx/u-boot-nand.lds
+++ b/arch/powerpc/cpu/mpc85xx/u-boot-nand.lds
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
-#include "config.h"	/* CONFIG_BOARDDIR */
+#include "config.h"
 
 #ifndef CONFIG_SYS_MONITOR_LEN
 #define CONFIG_SYS_MONITOR_LEN	0x80000