x86/xen: split off enlighten_pvh.c

Create enlighten_pvh.c by splitting off PVH related code from enlighten.c,
put it under CONFIG_XEN_PVH.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index cb0164a..348128b 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -15,6 +15,8 @@
 			grant-table.o suspend.o platform-pci-unplug.o \
 			p2m.o apic.o pmu.o
 
+obj-$(CONFIG_XEN_PVH)			+= enlighten_pvh.o
+
 obj-$(CONFIG_EVENT_TRACING) += trace.o
 
 obj-$(CONFIG_SMP)		+= smp.o