Remove old lguest I/O infrrasructure.

This patch gets rid of the old lguest host I/O infrastructure and
replaces it with a single hypercall "LHCALL_NOTIFY" which takes an
address.

The main change is the removal of io.c: that mainly did inter-guest
I/O, which virtio doesn't yet support.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/include/asm-x86/lguest_hcall.h b/include/asm-x86/lguest_hcall.h
index 0c553ef..f948491 100644
--- a/include/asm-x86/lguest_hcall.h
+++ b/include/asm-x86/lguest_hcall.h
@@ -13,11 +13,10 @@
 #define LHCALL_TS		8
 #define LHCALL_SET_CLOCKEVENT	9
 #define LHCALL_HALT		10
-#define LHCALL_BIND_DMA		12
-#define LHCALL_SEND_DMA		13
 #define LHCALL_SET_PTE		14
 #define LHCALL_SET_PMD		15
 #define LHCALL_LOAD_TLS		16
+#define LHCALL_NOTIFY		17
 
 /*G:031 First, how does our Guest contact the Host to ask for privileged
  * operations?  There are two ways: the direct way is to make a "hypercall",