env: Add support for UBI environment

UBI is a better place for the environment on NAND devices because it
handles wear-leveling and bad blocks.

Gluebi is needed in Linux to access the env as an MTD partition.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/common/Makefile b/common/Makefile
index f631311..0e0fff1 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -66,6 +66,7 @@
 COBJS-$(CONFIG_ENV_IS_IN_ONENAND) += env_onenand.o
 COBJS-$(CONFIG_ENV_IS_IN_SPI_FLASH) += env_sf.o
 COBJS-$(CONFIG_ENV_IS_IN_REMOTE) += env_remote.o
+COBJS-$(CONFIG_ENV_IS_IN_UBI) += env_ubi.o
 COBJS-$(CONFIG_ENV_IS_NOWHERE) += env_nowhere.o
 
 # command