env: Move env_get() to env.h

Move env_get() 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/freescale/mpc837xemds/pci.c b/board/freescale/mpc837xemds/pci.c
index 4217638..41b78cf 100644
--- a/board/freescale/mpc837xemds/pci.c
+++ b/board/freescale/mpc837xemds/pci.c
@@ -6,6 +6,7 @@
 #include <asm/mmu.h>
 #include <asm/io.h>
 #include <common.h>
+#include <env.h>
 #include <mpc83xx.h>
 #include <pci.h>
 #include <i2c.h>