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>

include/init.h

@@ -213,6 +213,7 @@ int set_cpu_clk_info(void);
 int update_flash_size(int flash_size);
 int arch_early_init_r(void);
 void pci_init(void);
+void pci_ep_init(void);
 int misc_init_r(void);
 #if defined(CONFIG_VID)
 int init_func_vid(void);