x86: Support QEMU x86 targets

This commit introduces the initial U-Boot support for QEMU x86 targets.
U-Boot can boot from coreboot as a payload, or directly without coreboot.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Merged in patch 'x86: qemu: Add CMD_NET to qemu-x86_defconfig
   https://patchwork.ozlabs.org/patch/479745/
diff --git a/board/emulation/qemu-x86/start.S b/board/emulation/qemu-x86/start.S
new file mode 100644
index 0000000..a71db69
--- /dev/null
+++ b/board/emulation/qemu-x86/start.S
@@ -0,0 +1,9 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+.globl early_board_init
+early_board_init:
+	jmp	early_board_init_ret