x86, hyper: Change hypervisor detection order

Detect Xen before HyperV because in Viridian compatibility mode Xen
presents itself as HyperV.  Move Xen to the top since it seems more
likely that Xen would emulate VMware than vice versa.
Signed-off-by: NAnupam Chanda <achanda@nicira.com>
Link: http://lkml.kernel.org/r/1310150570-26810-1-git-send-email-achanda@nicira.comAcked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NYaozu (Eddie) Dong <eddie.dong@intel.com>
Reviewed-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/cpu/hypervisor.c

@@ -32,11 +32,11 @@
  */
 static const __initconst struct hypervisor_x86 * const hypervisors[] =
 {
-	&x86_hyper_vmware,
-	&x86_hyper_ms_hyperv,
 #ifdef CONFIG_XEN_PVHVM
 	&x86_hyper_xen_hvm,
 #endif
+	&x86_hyper_vmware,
+	&x86_hyper_ms_hyperv,
 };
 
 const struct hypervisor_x86 *x86_hyper;