part: Drop disk_partition_t typedef

We should not be using typedefs and these make it harder to use
forward declarations (to reduce header file inclusions). Drop the typedef.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index 96ca276..ad71f5a 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -227,7 +227,7 @@
 }
 
 int ext4fs_probe(struct blk_desc *fs_dev_desc,
-		 disk_partition_t *fs_partition)
+		 struct disk_partition *fs_partition)
 {
 	ext4fs_set_blk_dev(fs_dev_desc, fs_partition);