env: Move env_set() to env.h

Move env_set() over to the new header file.

Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/siemens/common/factoryset.c b/board/siemens/common/factoryset.c
index 9661542..cd224a8 100644
--- a/board/siemens/common/factoryset.c
+++ b/board/siemens/common/factoryset.c
@@ -8,6 +8,7 @@
 #if !defined(CONFIG_SPL_BUILD)
 
 #include <common.h>
+#include <env.h>
 #include <environment.h>
 #include <i2c.h>
 #include <asm/io.h>
diff --git a/board/siemens/draco/board.c b/board/siemens/draco/board.c
index 95b89da..a6840b8 100644
--- a/board/siemens/draco/board.c
+++ b/board/siemens/draco/board.c
@@ -13,6 +13,7 @@
  */
 
 #include <common.h>
+#include <env.h>
 #include <errno.h>
 #include <spl.h>
 #include <asm/arch/cpu.h>
diff --git a/board/siemens/pxm2/board.c b/board/siemens/pxm2/board.c
index 1b9e83e..0a82a5e 100644
--- a/board/siemens/pxm2/board.c
+++ b/board/siemens/pxm2/board.c
@@ -13,6 +13,7 @@
  */
 
 #include <common.h>
+#include <env.h>
 #include <environment.h>
 #include <errno.h>
 #include <spl.h>
diff --git a/board/siemens/rut/board.c b/board/siemens/rut/board.c
index 25e2ed2..539ecef 100644
--- a/board/siemens/rut/board.c
+++ b/board/siemens/rut/board.c
@@ -11,6 +11,7 @@
  */
 
 #include <common.h>
+#include <env.h>
 #include <errno.h>
 #include <spi.h>
 #include <spl.h>
diff --git a/board/siemens/taurus/taurus.c b/board/siemens/taurus/taurus.c
index 6ea97eb..d0efb67 100644
--- a/board/siemens/taurus/taurus.c
+++ b/board/siemens/taurus/taurus.c
@@ -14,6 +14,7 @@
 #include <command.h>
 #include <common.h>
 #include <dm.h>
+#include <env.h>
 #include <environment.h>
 #include <asm/io.h>
 #include <asm/arch/at91sam9260_matrix.h>