x86: efi-x86_payload: Enumerate PCI bus during early boot

The generic efi payload currently does not enumerate the PCI bus,
which means peripherals on the PCI bus are not discovered by their
drivers. This uses board_early_init_r() to do the PCI enumeration.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

board/efi/efi-x86_payload/Kconfig

@@ -17,6 +17,7 @@ config SYS_TEXT_BASE
 
 config BOARD_SPECIFIC_OPTIONS # dummy
 	def_bool y
+	select BOARD_EARLY_INIT_R
 	imply SYS_NS16550
 	imply SCSI
 	imply SCSI_AHCI

board/efi/efi-x86_payload/Makefile

@@ -2,4 +2,4 @@
 #
 # Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
 
-obj-y	+= start.o
+obj-y	+= start.o payload.o

board/efi/efi-x86_payload/payload.c

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <usb.h>
+
+int board_early_init_r(void)
+{
+	/*
+	 * Make sure PCI bus is enumerated so that peripherals on the PCI bus
+	 * can be discovered by their drivers
+	 */
+	pci_init();
+
+	return 0;
+}