PCI: consolidate the PCI_DOMAINS and PCI_DOMAINS_GENERIC config options

Move the definitions to drivers/pci and let the architectures select
them.  Two small differences to before: PCI_DOMAINS_GENERIC now selects
PCI_DOMAINS, cutting down the churn for modern architectures.  As the
only architectured arm did previously also offer PCI_DOMAINS as a user
visible choice in addition to selecting it from the relevant configs,
this is gone now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 4dec745..7cf4b8b 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -15,6 +15,7 @@
 	select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
 	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
 	select FORCE_PCI if (!IA64_HP_SIM)
+	select PCI_DOMAINS if PCI
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_EXIT_THREAD
 	select HAVE_IDE
@@ -544,9 +545,6 @@
 
 menu "Bus options (PCI, PCMCIA)"
 
-config PCI_DOMAINS
-	def_bool PCI
-
 config PCI_SYSCALL
 	def_bool PCI