x86: Add generic EFI payload support

It is possible to create a generic EFI payload for all x86 boards.
The payload is configured to include as many generic drivers as
possible. All stuff that touches low-level initialization are not
allowed as such is the EFI BIOS's responsibility. Platform specific
drivers (like gpio, spi, etc) are not included.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/board/efi/efi-x86_payload/start.S b/board/efi/efi-x86_payload/start.S
new file mode 100644
index 0000000..f7eaa7c
--- /dev/null
+++ b/board/efi/efi-x86_payload/start.S
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+.globl early_board_init
+early_board_init:
+	jmp	early_board_init_ret