add triple fault request support

if vcpu meet triple fault, the vcpu should exit.

Signed-off-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Tian, Kevin <kevin.tian@intel.com>

hypervisor/include/lib/errno.h

@@ -41,5 +41,7 @@
 #define EIO                4
 /** Indicates that target is busy. */
 #define EBUSY              5
+/** Indicates there is fault. */
+#define EFAULT             6
 
 #endif /* ERRNO_H */