xen: Remove hanging references to CONFIG_XEN_PLATFORM_PCI

In 5fbdc10395 the XEN_PLATFORM_PCI config
option was removed, but references in header files remained. Clean up
those references.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

include/xen/platform_pci.h

@@ -29,8 +29,7 @@
 static inline int xen_must_unplug_nics(void) {
 #if (defined(CONFIG_XEN_NETDEV_FRONTEND) || \
 		defined(CONFIG_XEN_NETDEV_FRONTEND_MODULE)) && \
-		(defined(CONFIG_XEN_PLATFORM_PCI) || \
-		 defined(CONFIG_XEN_PLATFORM_PCI_MODULE))
+		defined(CONFIG_XEN_PVHVM)
         return 1;
 #else
         return 0;
@@ -40,8 +39,7 @@ static inline int xen_must_unplug_nics(void) {
 static inline int xen_must_unplug_disks(void) {
 #if (defined(CONFIG_XEN_BLKDEV_FRONTEND) || \
 		defined(CONFIG_XEN_BLKDEV_FRONTEND_MODULE)) && \
-		(defined(CONFIG_XEN_PLATFORM_PCI) || \
-		 defined(CONFIG_XEN_PLATFORM_PCI_MODULE))
+		defined(CONFIG_XEN_PVHVM)
         return 1;
 #else
         return 0;