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/configs/durian_defconfig b/configs/durian_defconfig
index 158fec2..b44fd90 100644
--- a/configs/durian_defconfig
+++ b/configs/durian_defconfig
@@ -7,6 +7,7 @@
 CONFIG_ENV_SIZE=0x1000
 CONFIG_DEFAULT_DEVICE_TREE="phytium-durian"
 # CONFIG_PSCI_RESET is not set
+CONFIG_SYS_PCI_64BIT=y
 CONFIG_AHCI=y
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_SYS_LOAD_ADDR=0x90000000