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/arch/x86/cpu/qemu/Kconfig b/arch/x86/cpu/qemu/Kconfig
new file mode 100644
index 0000000..fb775d7
--- /dev/null
+++ b/arch/x86/cpu/qemu/Kconfig
@@ -0,0 +1,21 @@
+#
+# Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+config QEMU
+	bool
+	select TSC_CALIBRATION_BYPASS
+
+if QEMU
+
+config SYS_CAR_ADDR
+	hex
+	default 0xd0000
+
+config SYS_CAR_SIZE
+	hex
+	default 0x10000
+
+endif