PCI: consolidate the PCI_SYSCALL symbol

Let architectures select the syscall support instead of duplicating the
kconfig entry.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

drivers/pci/Kconfig

@@ -30,6 +30,9 @@ config PCI_DOMAINS_GENERIC
 	depends on PCI
 	select PCI_DOMAINS
 
+config PCI_SYSCALL
+	bool
+
 source "drivers/pci/pcie/Kconfig"
 
 config PCI_MSI