Add IPMI OEM command LinuxBootDone

Add a new OEM command for LinuxBoot to notify the BMC when it is about
to kexec into the OS. This is intended to give the BMC a chance to
prepare for an untrusted OS, e.g. disable any interfaces it doesn't want
the OS to have access to.

Tested:
Exercised the new OEM command using ipmitool
$ ipmitool raw 0x2e 0x32 0x79 0x2b 0x00 0x11
  79 2b 00 11

Change-Id: Ica76d77cdde48cebfbced32d8e7e860b559074e8
Signed-off-by: John Wedig <johnwedig@google.com>
diff --git a/ipmi.cpp b/ipmi.cpp
index 636cfa5..8e47c45 100644
--- a/ipmi.cpp
+++ b/ipmi.cpp
@@ -24,6 +24,7 @@
 #include "google_accel_oob.hpp"
 #include "handler.hpp"
 #include "host_power_off.hpp"
+#include "linux_boot_done.hpp"
 #include "machine_name.hpp"
 #include "pcie_bifurcation.hpp"
 #include "pcie_i2c.hpp"
@@ -83,6 +84,8 @@
             return accelOobWrite(data, handler);
         case SysPCIeSlotBifurcation:
             return pcieBifurcation(data, handler);
+        case SysLinuxBootDone:
+            return linuxBootDone(data, handler);
         default:
             std::fprintf(stderr, "Invalid subcommand: 0x%x\n", cmd);
             return ::ipmi::responseInvalidCommand();