Add crossystem support for nvram_cleared and kern_nv

Fix try_b processing

And move key block flags check up in LoadFirmware(), which speeds up
boot when the dev switch is off because it doesn't do a signature
check and then throw it out.

BUG=12282
TEST=build firmware, try by hand

Review URL: http://codereview.chromium.org/6596081

Change-Id: I10474e9e0ae324906dfe02a351347d04ce847f67
diff --git a/utility/crossystem_main.c b/utility/crossystem_main.c
index ebd6ed5..35d6ea7 100644
--- a/utility/crossystem_main.c
+++ b/utility/crossystem_main.c
@@ -43,10 +43,11 @@
   {"ecfw_act", 1, 0, "Active EC firmware"},
   {"kernkey_vfy", 1, 0, "Type of verification done on kernel key block"},
   /* Writable integers */
+  {"nvram_cleared", 0, 1, "Have NV settings been lost?  Write 0 to clear"},
+  {"kern_nv", 0, 1, "Non-volatile field for kernel use", "0x%08x"},
   {"recovery_request", 0, 1, "Recovery mode request (writable)"},
   {"dbg_reset", 0, 1, "Debug reset mode request (writable)"},
   {"fwb_tries", 0, 1, "Try firmware B count (writable)"},
-  {"kern_nv", 0, 1, "Non-volatile field for kernel use", "0x%08x"},
 
   /* TODO: implement the following:
    *   nvram_cleared