x86: dm: Clean up cpu drivers

This commit does the following to clean up x86 cpu dm drivers:
- Move cpu_x86 driver codes from arch/x86/cpu/cpu.c to a dedicated
  file arch/x86/cpu/cpu_x86.c
- Rename x86_cpu_get_desc() to cpu_x86_get_desc() to keep consistent
  naming with other dm drivers
- Add a new cpu_x86_bind() in the cpu_x86 driver which does exactly
  the same as the one in the intel baytrail cpu driver
- Update intel baytrail cpu driver to use cpu_x86_get_desc() and
  cpu_x86_bind()

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/cpu_x86.c b/arch/x86/cpu/cpu_x86.c
new file mode 100644
index 0000000..d32ba66
--- /dev/null
+++ b/arch/x86/cpu/cpu_x86.c
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <cpu.h>
+#include <dm.h>
+#include <errno.h>
+#include <asm/cpu.h>
+
+int cpu_x86_bind(struct udevice *dev)
+{
+	struct cpu_platdata *plat = dev_get_parent_platdata(dev);
+
+	plat->cpu_id = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+				      "intel,apic-id", -1);
+
+	return 0;
+}
+
+int cpu_x86_get_desc(struct udevice *dev, char *buf, int size)
+{
+	if (size < CPU_MAX_NAME_LEN)
+		return -ENOSPC;
+
+	cpu_get_name(buf);
+
+	return 0;
+}
+
+static const struct cpu_ops cpu_x86_ops = {
+	.get_desc	= cpu_x86_get_desc,
+};
+
+static const struct udevice_id cpu_x86_ids[] = {
+	{ .compatible = "cpu-x86" },
+	{ }
+};
+
+U_BOOT_DRIVER(cpu_x86_drv) = {
+	.name		= "cpu_x86",
+	.id		= UCLASS_CPU,
+	.of_match	= cpu_x86_ids,
+	.bind		= cpu_x86_bind,
+	.ops		= &cpu_x86_ops,
+};