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/cmd/read.c b/cmd/read.c
index 82c2d9a..7977e9d 100644
--- a/cmd/read.c
+++ b/cmd/read.c
@@ -18,7 +18,7 @@
 	struct blk_desc *dev_desc = NULL;
 	int dev;
 	int part = 0;
-	disk_partition_t part_info;
+	struct disk_partition part_info;
 	ulong offset = 0u;
 	ulong limit = 0u;
 	void *addr;