xen: arm: do not pass a machine ID to dom0

Xen relies on DTB and we pass in a suitable device-tree so we don't
need to (and shouldn't) pretend to be a Versatile Express here.

We already don't pass a machine ID to domU in the same way.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

xen/arch/arm/domain_build.c

@@ -349,7 +349,7 @@ int construct_dom0(struct domain *d)
  */
 
     regs->r0 = 0; /* SBZ */
-    regs->r1 = 2272; /* Machine NR: Versatile Express */
+    regs->r1 = 0xffffffff; /* We use DTB therefore no machine id */
     regs->r2 = kinfo.dtb_paddr;
 
     WRITE_CP32(SCTLR_BASE, SCTLR);