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/bootefi.c b/cmd/bootefi.c
index 8ab0ff5..3041873 100644
--- a/cmd/bootefi.c
+++ b/cmd/bootefi.c
@@ -281,7 +281,7 @@
 		return EFI_SUCCESS;
 	}
 #else
-	bootm_headers_t img = { 0 };
+	struct bootm_headers img = { 0 };
 	efi_status_t ret;
 
 	if (fdt == EFI_FDT_USE_INTERNAL) {