env: ubi: Add missing ENV_NAME

Add missing environment name for UBI, to prevent this NULL in output:
Loading Environment from <NULL>...
and rather have a valid UBI there:
Loading Environment from UBI...

Signed-off-by: Marek Vasut <marex@denx.de>

env/ubi.c

@@ -168,6 +168,7 @@ static int env_ubi_load(void)
 
 U_BOOT_ENV_LOCATION(ubi) = {
 	.location	= ENVL_UBI,
+	ENV_NAME("UBI")
 	.load		= env_ubi_load,
 	.save		= env_save_ptr(env_ubi_save),
 };