Add cros_debug option to crossystem

Change-Id: Ie62364a87f7f144ee647054d2a9ef83522cdbe7d

BUG=12904
TEST=manual

Expected output of `crossystem mainfw_type cros_debug` under each of the following scenarios:

* Boot Alex with dev switch off: normal 0
* Boot Alex with dev switch on (and dev firmware): developer 1
* Boot Alex with dev switch on (and normal firmware): normal 1
* Boot Alex with recovery firmware: recovery 0
* Boot Alex with dev switch off, then turn the dev switch on after booting: normal 0
* Boot Cr-48 with dev switch off: normal 0
* Boot Cr-48 with dev switch on: developer 1
* Boot Cr-48 with recovery firmware: recovery 0

* Boot Alex with dev switch off and kernel command line changed to include "cros_debug": normal 1
* Boot Alex with dev switch off and kernel command line changed to include "cros_debugg": normal 0
* Boot Alex with dev switch off and kernel command line changed to include "ccros_debug": normal 0

* Boot H2O BIOS with kernel command line changed to include "cros_debug": nonchrome 1
* Boot H2O BIOS with kernel command line changed to include "cros_debugg": nonchrome 0
* Boot H2O BIOS with kernel command line changed to include "ccros_debug": nonchrome 0

Review URL: http://codereview.chromium.org/6659021
diff --git a/utility/crossystem_main.c b/utility/crossystem_main.c
index 35d6ea7..584de59 100644
--- a/utility/crossystem_main.c
+++ b/utility/crossystem_main.c
@@ -34,6 +34,7 @@
   {"savedmem_size", 0, 0, "RAM debug data area size in bytes"},
   {"fmap_base", 0, 0, "Main firmware flashmap physical address", "0x%08x"},
   {"tried_fwb", 0, 0, "Tried firmware B before A this boot"},
+  {"cros_debug", 0, 0, "OS should allow debug features"},
   /* Read-only strings */
   {"hwid", 1, 0, "Hardware ID"},
   {"fwid", 1, 0, "Active firmware ID"},