warp7: hab: Set environment variable indicating HAB enable

This patch adds an environment variable called "hab_enabled" which gets set
to a boolean status indicating whether HAB is enabled or not.

Subsequent patches can use this environment variable to determine if its
necessary to run a given binary through the hab_auth_img console command.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
diff --git a/include/configs/warp7.h b/include/configs/warp7.h
index 98fedb8..10db716 100644
--- a/include/configs/warp7.h
+++ b/include/configs/warp7.h
@@ -139,4 +139,7 @@
 
 #define CONFIG_USBNET_DEV_ADDR		"de:ad:be:af:00:01"
 
+/* Environment variable name to represent HAB enable state */
+#define HAB_ENABLED_ENVNAME		"hab_enabled"
+
 #endif