Capitalized "[Return]" to adhere to code standards.

Capitalized "[Return]" in places it wasn't.
This commit is style changes only.

Change-Id: I218c87c136ead38af3e310aa2711efaa00df2ca4
Signed-off-by: Gunnar Mills <gmills@us.ibm.com>
diff --git a/lib/boot/reboots.robot b/lib/boot/reboots.robot
index c931ab6..314e10b 100644
--- a/lib/boot/reboots.robot
+++ b/lib/boot/reboots.robot
@@ -64,7 +64,7 @@
 
     ${uptime}  ${idle_time}=  Split String  ${uptime_string}  ${SPACE}
 
-    [return]  ${uptime}
+    [Return]  ${uptime}
 
 Reboot BMC
     Start Command  /sbin/reboot