pci: Add Rockchip dwc based PCIe controller driver

Add Rockchip dwc based PCIe controller driver for rk356x platform.
Driver support Gen3 by operating as a Root complex.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Kever Yang<kever.yang@rock-chips.com>
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 8b4d49a..5ed94bc 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -48,5 +48,6 @@
 obj-$(CONFIG_PCI_KEYSTONE) += pcie_dw_ti.o
 obj-$(CONFIG_PCIE_MEDIATEK) += pcie_mediatek.o
 obj-$(CONFIG_PCIE_ROCKCHIP) += pcie_rockchip.o
+obj-$(CONFIG_PCIE_DW_ROCKCHIP) += pcie_dw_rockchip.o
 obj-$(CONFIG_PCI_BRCMSTB) += pcie_brcmstb.o
 obj-$(CONFIG_PCI_OCTEONTX) += pci_octeontx.o