PCI: Add driver for a 'pci-host-ecam-generic' host controller

QEMU emulates such a device with '-machine virt,highmem=off' on ARM.
The 'highmem=off' part is required for things to work as the PCI code
in U-Boot doesn't seem to support 64-bit BARs.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 8af2470..58f128d 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -33,6 +33,14 @@
 	help
 	  Enable PCI memory and I/O space resource allocation and assignment.
 
+config PCIE_ECAM_GENERIC
+	bool "Generic ECAM-based PCI host controller support"
+	default n
+	depends on DM_PCI
+	help
+	  Say Y here if you want to enable support for generic ECAM-based
+	  PCIe host controllers, such as the one emulated by QEMU.
+
 config PCIE_DW_MVEBU
 	bool "Enable Armada-8K PCIe driver (DesignWare core)"
 	depends on DM_PCI