xen-hvm: Fix xen_hvm_init() to adjust pc memory layout

This is just below_4g_mem_size and above_4g_mem_size which is used later in QEMU.

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Don Slutz <dslutz@verizon.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/xen-hvm-stub.c b/xen-hvm-stub.c
index 4eb27b5..2d98696 100644
--- a/xen-hvm-stub.c
+++ b/xen-hvm-stub.c
@@ -51,7 +51,8 @@
 {
 }
 
-int xen_hvm_init(MemoryRegion **ram_memory)
+int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
+                 MemoryRegion **ram_memory)
 {
     return 0;
 }