blk: Call part_init() in the post_probe() method

part_init() is currently called in every DM BLK driver, either
in its bind() or probe() method. However we can use the BLK
uclass driver's post_probe() method to do it automatically.

Update all DM BLK drivers to adopt this change.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
index facf527..95e7b54 100644
--- a/drivers/block/blk-uclass.c
+++ b/drivers/block/blk-uclass.c
@@ -644,8 +644,20 @@
 	return 0;
 }
 
+static int blk_post_probe(struct udevice *dev)
+{
+#if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_LIBDISK_SUPPORT)
+	struct blk_desc *desc = dev_get_uclass_platdata(dev);
+
+	part_init(desc);
+#endif
+
+	return 0;
+}
+
 UCLASS_DRIVER(blk) = {
 	.id		= UCLASS_BLK,
 	.name		= "blk",
+	.post_probe	= blk_post_probe,
 	.per_device_platdata_auto_alloc_size = sizeof(struct blk_desc),
 };