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/CarMediaLab/flea3/flea3.c b/board/CarMediaLab/flea3/flea3.c
index 9eec1b7..be0bc22 100644
--- a/board/CarMediaLab/flea3/flea3.c
+++ b/board/CarMediaLab/flea3/flea3.c
@@ -9,6 +9,7 @@
 
 #include <common.h>
 #include <asm/io.h>
+#include <env.h>
 #include <linux/errno.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/arch/crm_regs.h>