cmd: host: fix seg fault at "host info"

With the patch below applied, host_block_dev structure was switched
to be placed in platdata rather than priv. The command "host info"
must be aligned with this change. Otherwise, we will see "Segmentation
Fault."

Fixes: 8f994c860d91 ("sandbox: blk: Switch to use platdata_auto_alloc_size for the driver data")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/cmd/host.c b/cmd/host.c
index f7d3eae..98c4d2a 100644
--- a/cmd/host.c
+++ b/cmd/host.c
@@ -89,7 +89,7 @@
 		struct host_block_dev *host_dev;
 
 #ifdef CONFIG_BLK
-		host_dev = dev_get_priv(blk_dev->bdev);
+		host_dev = dev_get_platdata(blk_dev->bdev);
 #else
 		host_dev = blk_dev->priv;
 #endif