treewide: Drop bootm_headers_t typedef

This is not needed and we should avoid typedefs. Use the struct instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/bootz.c b/cmd/bootz.c
index 4f024bd..f142357 100644
--- a/cmd/bootz.c
+++ b/cmd/bootz.c
@@ -25,7 +25,7 @@
  * zImage booting support
  */
 static int bootz_start(struct cmd_tbl *cmdtp, int flag, int argc,
-		       char *const argv[], bootm_headers_t *images)
+		       char *const argv[], struct bootm_headers *images)
 {
 	int ret;
 	ulong zi_start, zi_end;