xen-hvm: Constify string

It's constant, and sourced from existing const strings. Avoid dodgy
casts by converting to const.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

xen-hvm.c

diff --git a/xen-hvm.c b/xen-hvm.c
index 91de2e2..d763e86 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -71,7 +71,7 @@
 typedef struct XenPhysmap {
     hwaddr start_addr;
     ram_addr_t size;
-    char *name;
+    const char *name;
     hwaddr phys_offset;
 
     QLIST_ENTRY(XenPhysmap) list;
@@ -330,7 +330,7 @@
 
     physmap->start_addr = start_addr;
     physmap->size = size;
-    physmap->name = (char *)mr->name;
+    physmap->name = mr->name;
     physmap->phys_offset = phys_offset;
 
     QLIST_INSERT_HEAD(&state->physmap, physmap, list);