sandbox: blk: Switch to use platdata_auto_alloc_size for the driver data

Currently the sandbox block driver uses priv_auto_alloc_size for
the driver data, however that's only available after the device
probe phase. In order to make it accessible in an earlier phase,
switch to use platdata_auto_alloc_size instead.

This patch is the prerequisite for the follow up patch of DM BLK
driver changes to work with Sandbox.

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

drivers/block/sandbox.c

@@ -33,7 +33,7 @@ static unsigned long host_block_read(struct udevice *dev,
 				     unsigned long start, lbaint_t blkcnt,
 				     void *buffer)
 {
-	struct host_block_dev *host_dev = dev_get_priv(dev);
+	struct host_block_dev *host_dev = dev_get_platdata(dev);
 	struct blk_desc *block_dev = dev_get_uclass_platdata(dev);
 
 #else
@@ -64,7 +64,7 @@ static unsigned long host_block_write(struct udevice *dev,
 				      unsigned long start, lbaint_t blkcnt,
 				      const void *buffer)
 {
-	struct host_block_dev *host_dev = dev_get_priv(dev);
+	struct host_block_dev *host_dev = dev_get_platdata(dev);
 	struct blk_desc *block_dev = dev_get_uclass_platdata(dev);
 #else
 static unsigned long host_block_write(struct blk_desc *block_dev,
@@ -131,16 +131,17 @@ int host_dev_bind(int devnum, char *filename)
 				os_lseek(fd, 0, OS_SEEK_END) / 512, &dev);
 	if (ret)
 		goto err_file;
+
+	host_dev = dev_get_platdata(dev);
+	host_dev->fd = fd;
+	host_dev->filename = fname;
+
 	ret = device_probe(dev);
 	if (ret) {
 		device_unbind(dev);
 		goto err_file;
 	}
 
-	host_dev = dev_get_priv(dev);
-	host_dev->fd = fd;
-	host_dev->filename = fname;
-
 	return blk_prepare_device(dev);
 err_file:
 	os_close(fd);
@@ -226,7 +227,7 @@ U_BOOT_DRIVER(sandbox_host_blk) = {
 	.name		= "sandbox_host_blk",
 	.id		= UCLASS_BLK,
 	.ops		= &sandbox_host_blk_ops,
-	.priv_auto_alloc_size	= sizeof(struct host_block_dev),
+	.platdata_auto_alloc_size = sizeof(struct host_block_dev),
 };
 #else
 U_BOOT_LEGACY_BLK(sandbox_host) = {