Fix for field mode not working after reboot

This commit fixes a problem with field mode - namely, that the file
location for environment variables was moved. The new path is now
referenced when checking field mode status after a reboot.

Resolves openbmc/openbmc#2428

Change-Id: I68b5d2a3ce6e2aa0b2c3825bc56e02d6bf581e9d
Signed-off-by: Michael Tritz <mtritz@us.ibm.com>
diff --git a/item_updater.cpp b/item_updater.cpp
index 2c23b93..2282c28 100644
--- a/item_updater.cpp
+++ b/item_updater.cpp
@@ -470,7 +470,7 @@
 
 void ItemUpdater::restoreFieldModeStatus()
 {
-    std::ifstream input("/run/fw_env");
+    std::ifstream input("/dev/mtd/u-boot-env");
     std::string envVar;
     std::getline(input, envVar);