xen: remove XEN_PLATFORM_PCI config option

Xen PVHVM needs xen-platform-pci, on the other hand xen-platform-pci is
useless in any other cases.
Therefore remove the XEN_PLATFORM_PCI config option and compile
xen-platform-pci built-in if XEN_PVHVM is selected.

Changes to v1:

- remove xen-platform-pci.o and just use platform-pci.o since it is not
externally visible anymore.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/Kconfig

@@ -137,16 +137,6 @@ config XEN_GRANT_DEV_ALLOC
 	  to other domains. This can be used to implement frontend drivers
 	  or as part of an inter-domain shared memory channel.
 
-config XEN_PLATFORM_PCI
-	tristate "xen platform pci device driver"
-	depends on XEN_PVHVM && PCI
-	default m
-	help
-	  Driver for the Xen PCI Platform device: it is responsible for
-	  initializing xenbus and grant_table when running in a Xen HVM
-	  domain. As a consequence this driver is required to run any Xen PV
-	  frontend on Xen HVM.
-
 config SWIOTLB_XEN
 	def_bool y
 	depends on PCI

drivers/xen/Makefile

@@ -14,7 +14,7 @@ obj-$(CONFIG_XEN_GNTDEV)		+= xen-gntdev.o
 obj-$(CONFIG_XEN_GRANT_DEV_ALLOC)	+= xen-gntalloc.o
 obj-$(CONFIG_XENFS)			+= xenfs/
 obj-$(CONFIG_XEN_SYS_HYPERVISOR)	+= sys-hypervisor.o
-obj-$(CONFIG_XEN_PLATFORM_PCI)		+= xen-platform-pci.o
+obj-$(CONFIG_XEN_PVHVM)			+= platform-pci.o
 obj-$(CONFIG_XEN_TMEM)			+= tmem.o
 obj-$(CONFIG_SWIOTLB_XEN)		+= swiotlb-xen.o
 obj-$(CONFIG_XEN_DOM0)			+= pci.o
@@ -23,5 +23,3 @@ obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= xen-pciback/
 xen-evtchn-y				:= evtchn.o
 xen-gntdev-y				:= gntdev.o
 xen-gntalloc-y				:= gntalloc.o
-
-xen-platform-pci-y			:= platform-pci.o