rename environment.c in env_embedded.c to reflect is functionality

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/board/sixnet/u-boot.lds b/board/sixnet/u-boot.lds
index b91c44a..974e45c 100644
--- a/board/sixnet/u-boot.lds
+++ b/board/sixnet/u-boot.lds
@@ -53,7 +53,7 @@
   .text      :
   {
     cpu/mpc8xx/start.o	(.text)
-    common/environment.o(.text)
+    common/env_embedded.o(.text)
     *(.text)
     *(.fixup)
     *(.got1)