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/handler_impl.hpp b/handler_impl.hpp
index 677efa2..807114e 100644
--- a/handler_impl.hpp
+++ b/handler_impl.hpp
@@ -34,6 +34,7 @@
     std::string getMachineName() override;
     void buildI2cPcieMapping() override;
     size_t getI2cPcieMappingSize() const override;
+    void hostPowerOffDelay(std::uint32_t delay) const override;
     std::tuple<std::uint32_t, std::string>
         getI2cEntry(unsigned int entry) const override;