xen: XEN_PVHVM depends on PCI

Xen PV on HVM guests require PCI support because they need the
xen-platform-pci driver in order to initialize xenbus.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/Kconfig

@@ -25,8 +25,7 @@ config XEN_PRIVILEGED_GUEST
 
 config XEN_PVHVM
 	def_bool y
-	depends on XEN
-	depends on X86_LOCAL_APIC
+	depends on XEN && PCI && X86_LOCAL_APIC
 
 config XEN_MAX_DOMAIN_MEMORY
        int