drivers: pci_ep: Introduce UCLASS_PCI_EP uclass

Introduce new UCLASS_PCI_EP class for handling PCI endpoint
devices, allowing to set various attributes of the PCI endpoint
device, such as:
* configuration space header
* BAR definitions
* outband memory mapping
* start/stop PCI link

Signed-off-by: Ramon Fried <ramon.fried@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 96ff4f5..5a9d01b 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -66,6 +66,8 @@
 
 source "drivers/pci/Kconfig"
 
+source "drivers/pci_endpoint/Kconfig"
+
 source "drivers/pch/Kconfig"
 
 source "drivers/pcmcia/Kconfig"