cpu: Add get_vendor callback

The CPU udevice already has a few callbacks to retreive information
about the currently running CPUs. This patch adds a new get_vendor()
call that returns the vendor of the main CPUs.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/include/asm/cpu_x86.h

@@ -31,4 +31,17 @@ int cpu_x86_bind(struct udevice *dev);
  */
 int cpu_x86_get_desc(struct udevice *dev, char *buf, int size);
 
+/**
+ * cpu_x86_get_vendor() - Get a vendor string for an x86 CPU
+ *
+ * This uses cpu_vendor_name() and is suitable to use as the get_vendor()
+ * method for the CPU uclass.
+ *
+ * @dev:	Device to check (UCLASS_CPU)
+ * @buf:	Buffer to place string
+ * @size:	Size of string space
+ * @return:	0 if OK, -ENOSPC if buffer is too small, other -ve on error
+ */
+int cpu_x86_get_vendor(struct udevice *dev, char *buf, int size);
+
 #endif /* _ASM_CPU_X86_H */