The PCI syscalls are built on every architecture except X86, but only
a few have ever hooked them up.  Use a new Kconfig symbol to save a
couple of kB on the architectures that have never used the syscalls.
Tested on x86 and ia64 only.
Signed-off-by: NMatthew Wilcox <matthew@wil.cx>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>