manifest layouts: add cros_boot_mode to platform/

oldlayout.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <manifest>
   <remote  name="cros"
            fetch="http://git.chromium.org/git"
            review="codereview.chromium.org" />
   <default revision="refs/heads/master"
            remote="cros" />
 
   <project path="src/platform/acpi" name="acpi" />
   <project path="src/platform/assets" name="assets" />
   <project path="src/platform/audioconfig" name="audioconfig" />
   <project path="src/platform/autox" name="autox" />
   <project path="src/platform/bootstat" name="bootstat" />
   <project path="src/platform/cashew" name="cashew" />
   <project path="src/platform/chromiumos-assets" name="chromiumos-assets" />
   <project path="src/platform/crash" name="crash" />
   <project path="src/platform/crash-dumper" name="crash-dumper" />
   <project path="src/platform/crash-reporter" name="crash-reporter" />
   <project path="src/platform/cromo" name="cromo" />
   <project path="src/platform/cros" name="cros" />
+  <project path="src/platform/cros_boot_mode" name="cros_boot_mode" />
   <project path="src/platform/cryptohome" name="cryptohome" />
   <project path="src/platform/dev" name="dev-util" />
   <project path="src/platform/dump-syms" name="dump-syms" />
   <project path="src/platform/entd" name="entd" />
   <project path="src/platform/factory_installer" name="factory_installer" />
   <project path="src/platform/firmware" name="firmware" />
   <project path="src/platform/firmware-utils" name="firmware-utils" />
   <project path="src/platform/recovery_installer" name="recovery_installer" />
   <project path="src/platform/image-burner" name="image-burner" />
   <project path="src/platform/init" name="init" />
@@ skipping 62 matching lines @@
   <project path="src/third_party/wpa_supplicant" name="hostap" />
   <project path="src/third_party/portage" name="portage" />
   <project path="src/third_party/chromiumos-overlay" name="chromiumos-overlay" />
   <project path="src/third_party/laptop-mode-tools" name="laptop-mode-tools" />
   <project path="src/third_party/modemmanager" name="modemmanager" />
   <project path="src/third_party/libresample" name="libresample" />
   <project path="src/third_party/rootdev" name="rootdev" />
   <project path="src/third_party/grub2" name="grub2" />
   <project path="src/third_party/dbus-c++" name="dbus-cplusplus" />
 </manifest>