pci_ep: Add the init function

Some EP deivces need to initialize before RC scan it, e.g. NXP
layerscape platform, so add the init function in pci_ep uclass.

Signed-off-by: Xiaowei Bao <xiaowei.bao@nxp.com>
Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/common/board_r.c b/common/board_r.c
index 67dc25c..d9307f0 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -233,6 +233,15 @@
 }
 #endif
 
+#ifdef CONFIG_PCI_ENDPOINT
+static int initr_pci_ep(void)
+{
+	pci_ep_init();
+
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_PCI
 static int initr_pci(void)
 {
@@ -816,6 +825,9 @@
 #ifdef CONFIG_BITBANGMII
 	initr_bbmii,
 #endif
+#ifdef CONFIG_PCI_ENDPOINT
+	initr_pci_ep,
+#endif
 #ifdef CONFIG_CMD_NET
 	INIT_FUNC_WATCHDOG_RESET
 	initr_net,