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/Makefile b/board/efi/efi-x86_payload/Makefile
new file mode 100644
index 0000000..6982340
--- /dev/null
+++ b/board/efi/efi-x86_payload/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+obj-y	+= start.o