Add kern_nv field to crossystem

Change-Id: Ifa5cc3bd8367a258fb720162572f450a1be99c03

BUG=none
TEST=manual

crossystem kern_nv=0x12345678
crossystem kern_nv

Review URL: http://codereview.chromium.org/6602040
diff --git a/utility/crossystem_main.c b/utility/crossystem_main.c
index 5352b4d..ebd6ed5 100644
--- a/utility/crossystem_main.c
+++ b/utility/crossystem_main.c
@@ -46,6 +46,7 @@
   {"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