Implement Get POH Counter command

It returns a counter value proportional to the system operating
power-on hours.

Partially Resolves openbmc/openbmc#2979

Change-Id: Ib0cd43fe5cbc055ae84991577d766bedae58d775
Signed-off-by: Nagaraju Goruganti <ngorugan@in.ibm.com>
diff --git a/chassishandler.h b/chassishandler.h
index c0e82a1..8643ae4 100644
--- a/chassishandler.h
+++ b/chassishandler.h
@@ -16,6 +16,7 @@
     // Get capability bits
     IPMI_CMD_SET_SYS_BOOT_OPTIONS = 0x08,
     IPMI_CMD_GET_SYS_BOOT_OPTIONS = 0x09,
+    IPMI_CMD_GET_POH_COUNTER      = 0x0F,
 };
 
 // Command specific completion codes