xen: add definitions for console_io

Those definitions added are used with HYPERVISOR_console_io().

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>

include/xen/interface/xen.h

@@ -76,6 +76,12 @@
 #define __HYPERVISOR_arch_6               54
 #define __HYPERVISOR_arch_7               55
 
+/*
+ * Commands to HYPERVISOR_console_io().
+ */
+#define CONSOLEIO_write         0
+#define CONSOLEIO_read          1
+
 #ifndef __ASSEMBLY__
 
 typedef u16 domid_t;