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/cmd/fat.c b/cmd/fat.c
index aae993d..82b9b38 100644
--- a/cmd/fat.c
+++ b/cmd/fat.c
@@ -69,7 +69,7 @@
 			 char * const argv[])
 {
 	int dev, part;
-	block_dev_desc_t *dev_desc;
+	struct blk_desc *dev_desc;
 	disk_partition_t info;
 
 	if (argc < 2) {
@@ -105,7 +105,7 @@
 	int ret;
 	unsigned long addr;
 	unsigned long count;
-	block_dev_desc_t *dev_desc = NULL;
+	struct blk_desc *dev_desc = NULL;
 	disk_partition_t info;
 	int dev = 0;
 	int part = 1;