Makefile: rename all libraries to built-in.o

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/board/rbc823/u-boot.lds b/board/rbc823/u-boot.lds
index 191f9eb..7676cf4 100644
--- a/board/rbc823/u-boot.lds
+++ b/board/rbc823/u-boot.lds
@@ -19,10 +19,10 @@
     arch/powerpc/cpu/mpc8xx/start.o	(.text*)
     arch/powerpc/cpu/mpc8xx/traps.o	(.text*)
 
-    lib/libgeneric.o			(.text*)
-    net/libnet.o			(.text*)
-    arch/powerpc/cpu/mpc8xx/libmpc8xx.o	(.text*)
-    arch/powerpc/lib/libpowerpc.o	(.text*)
+    lib/built-in.o			(.text*)
+    net/built-in.o			(.text*)
+    arch/powerpc/cpu/mpc8xx/built-in.o	(.text*)
+    arch/powerpc/lib/built-in.o		(.text*)
 
     . = env_offset;
     common/env_embedded.o		(.text*)