pci: Add Rockchip PCIe controller driver

Add Rockchip PCIe controller driver for rk3399 platform.

Driver support Gen1 by operating as a Root complex.

Thanks to Patrick for initial work.

Signed-off-by: Patrick Wildt <patrick@blueri.se>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Tested-by: Suniel Mahesh <sunil@amarulasolutions.com> #roc-rk3399-pc
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index c051ecc..493e935 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -43,3 +43,4 @@
 obj-$(CONFIG_PCIE_INTEL_FPGA) += pcie_intel_fpga.o
 obj-$(CONFIG_PCI_KEYSTONE) += pcie_dw_ti.o
 obj-$(CONFIG_PCIE_MEDIATEK) += pcie_mediatek.o
+obj-$(CONFIG_PCIE_ROCKCHIP) += pcie_rockchip.o