env: Rename environment.h to env_internal.h

This file contains lots of internal details about the environment. Most
code can include env.h instead, calling the functions there as needed.

Rename this file and add a comment at the top to indicate its internal
nature.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
[trini: Fixup apalis-tk1.c]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/env/fat.c b/env/fat.c
index d23753c..1836556 100644
--- a/env/fat.c
+++ b/env/fat.c
@@ -10,7 +10,7 @@
 
 #include <command.h>
 #include <env.h>
-#include <environment.h>
+#include <env_internal.h>
 #include <linux/stddef.h>
 #include <malloc.h>
 #include <memalign.h>