PCI: consolidate PCI config entry in drivers/pci

There is no good reason to duplicate the PCI menu in every architecture.
Instead provide a selectable HAVE_PCI symbol that indicates availability
of PCI support, and a FORCE_PCI symbol to for PCI on and the handle the
rest in drivers/pci.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

drivers/pci/Kconfig

@@ -3,6 +3,24 @@
 # PCI configuration
 #
 
+# select this to offer the PCI prompt
+config HAVE_PCI
+	bool
+
+# select this to unconditionally force on PCI support
+config FORCE_PCI
+	bool
+	select HAVE_PCI
+	select PCI
+
+menuconfig PCI
+	bool "PCI support"
+	depends on HAVE_PCI
+	help
+	  This option enables support for the PCI local bus, including
+	  support for PCI-X and the foundations for PCI Express support.
+	  Say 'Y' here unless you know what you are doing.
+
 source "drivers/pci/pcie/Kconfig"
 
 config PCI_MSI