Convert CONFIG_SYS_PCI_64BIT to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_PCI_64BIT

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index cc139af..42f8cb6 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -19,6 +19,12 @@
 	  measure when porting a board to use driver model for PCI. Once the
 	  board is fully supported, this option should be disabled.
 
+config SYS_PCI_64BIT
+	bool "Enable 64-bit PCI resources"
+	default y if PPC
+	help
+	  Enable 64-bit PCI resource access.
+
 config PCI_AARDVARK
 	bool "Enable Aardvark PCIe driver"
 	depends on DM_GPIO