Add crossystem arch (reports x86 or arm, depending on platform)

host/arch/arm/lib/crossystem_arch.c

Index: host/arch/arm/lib/crossystem_arch.c
diff --git a/host/arch/arm/lib/crossystem_arch.c b/host/arch/arm/lib/crossystem_arch.c
index 34f38f6e72e3e1871b5cd2d388b058721a3a93c9..4304ce7c596bf4432eedf317f8f99d6e1a3af4eb 100644
--- a/host/arch/arm/lib/crossystem_arch.c
+++ b/host/arch/arm/lib/crossystem_arch.c
@@ -75,7 +75,9 @@ int VbGetArchPropertyInt(const char* name) {
 const char* VbGetArchPropertyString(const char* name, char* dest, int size) {
   /* TODO: IMPLEMENT ME!  For now, return reasonable defaults for
    * values where reasonable defaults exist. */
-  if (!strcasecmp(name,"hwid")) {
+  if (!strcasecmp(name,"arch")) {
+    return StrCopy(dest, "arm", size);
+  } else if (!strcasecmp(name,"hwid")) {
     return StrCopy(dest, "UnknownArmHwid", size);
   } else if (!strcasecmp(name,"fwid")) {
     return StrCopy(dest, "UnknownArmFwid", size);