xen: missing includes

Changes in v2:
- remove pvclock hack;
- remove include linux/types.h from xen/interface/xen.h.
v3:
- Compile under IA64
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/tty/hvc/hvc_xen.c

@@ -21,6 +21,7 @@
 #include <linux/console.h>
 #include <linux/delay.h>
 #include <linux/err.h>
+#include <linux/irq.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/list.h>
@@ -35,6 +36,7 @@
 #include <xen/page.h>
 #include <xen/events.h>
 #include <xen/interface/io/console.h>
+#include <xen/interface/sched.h>
 #include <xen/hvc-console.h>
 #include <xen/xenbus.h>