Add last reset time to reboot bmc  page

- Timestamp is displayed to inform user of last
  power operation

Signed-off-by: Dixsie Wolmers <dixsie@ibm.com>
Change-Id: Ia4d95bced701b04f1099d020ee062f06d16ae8dc
diff --git a/src/locales/en-US.json b/src/locales/en-US.json
index cc99373..97f4578 100644
--- a/src/locales/en-US.json
+++ b/src/locales/en-US.json
@@ -496,6 +496,7 @@
     }
   },
   "pageRebootBmc": {
+    "lastReboot": "Last BMC reboot",
     "rebootBmc": "Reboot BMC",
     "rebootInformation": "When you reboot the BMC, your web browser loses contact with the BMC for several minutes. When the BMC is back online, you may need to log in again.",
     "modal": {