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>
diff --git a/arch/x86/cpu/ivybridge/model_206ax.c b/arch/x86/cpu/ivybridge/model_206ax.c
index b074367..09b5342 100644
--- a/arch/x86/cpu/ivybridge/model_206ax.c
+++ b/arch/x86/cpu/ivybridge/model_206ax.c
@@ -477,6 +477,7 @@
 	.get_desc	= cpu_x86_get_desc,
 	.get_info	= model_206ax_get_info,
 	.get_count	= model_206ax_get_count,
+	.get_vendor	= cpu_x86_get_vendor,
 };
 
 static const struct udevice_id cpu_x86_model_206ax_ids[] = {