colibri-imx6ull: improve env badblock management

Use the complete 512kb (4 blocks) nand partition reserved for u-boot
environment instead of just the first block, this allows the module to
have a working environment even if 3 blocks are bad.

Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
diff --git a/include/configs/colibri-imx6ull.h b/include/configs/colibri-imx6ull.h
index 787fe33..91f0f95 100644
--- a/include/configs/colibri-imx6ull.h
+++ b/include/configs/colibri-imx6ull.h
@@ -140,8 +140,9 @@
 	(CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_INIT_SP_OFFSET)
 
 /* environment organization */
-
-/* Environment in eMMC, before config block at the end of 1st "boot sector" */
+#if defined(CONFIG_ENV_IS_IN_NAND)
+#define CONFIG_ENV_RANGE	(4 * CONFIG_ENV_SIZE)
+#endif
 
 #ifdef CONFIG_TARGET_COLIBRI_IMX6ULL_NAND
 /* NAND stuff */