Add new google ipmi sys command: SysHostPowerOff

New google ipmi sys command to let the BMC knows host shutdown,
allow host to gracefully shutdown and disable the watchdog with given
time delay.

Signed-off-by: Yunyun Lin <linyuny@google.com>
Change-Id: I02171c9cfed57ae5d10d66b515e4ab7ee8856466
diff --git a/ipmi.cpp b/ipmi.cpp
index 2b71315..bcd2b4d 100644
--- a/ipmi.cpp
+++ b/ipmi.cpp
@@ -23,6 +23,7 @@
 #include "eth.hpp"
 #include "flash_size.hpp"
 #include "handler.hpp"
+#include "host_power_off.hpp"
 #include "machine_name.hpp"
 #include "pcie_i2c.hpp"
 #include "psu.hpp"
@@ -72,6 +73,8 @@
                                           handler);
         case SysGetFlashSize:
             return getFlashSize(reqBuf, replyCmdBuf, dataLen, handler);
+        case SysHostPowerOff:
+            return hostPowerOff(reqBuf, replyCmdBuf, dataLen, handler);
         default:
             std::fprintf(stderr, "Invalid subcommand: 0x%x\n", reqBuf[0]);
             return IPMI_CC_INVALID;