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/common/spl/spl_sata.c b/common/spl/spl_sata.c
index 3ba4c24..1719946 100644
--- a/common/spl/spl_sata.c
+++ b/common/spl/spl_sata.c
@@ -23,7 +23,7 @@
 int spl_sata_load_image(void)
 {
 	int err;
-	block_dev_desc_t *stor_dev;
+	struct blk_desc *stor_dev;
 
 	err = init_sata(CONFIG_SPL_SATA_BOOT_DEVICE);
 	if (err) {