dm: Drop the block_dev_desc_t typedef

Use 'struct' instead of a typdef. Also since 'struct block_dev_desc' is long
and causes 80-column violations, rename it to struct blk_desc.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
index a992a00..168ae2b 100644
--- a/fs/ubifs/ubifs.c
+++ b/fs/ubifs/ubifs.c
@@ -561,7 +561,7 @@
 	return 0;
 }
 
-int ubifs_set_blk_dev(block_dev_desc_t *rbdd, disk_partition_t *info)
+int ubifs_set_blk_dev(struct blk_desc *rbdd, disk_partition_t *info)
 {
 	if (rbdd) {
 		debug("UBIFS cannot be used with normal block devices\n");