patch 8.2.4241: some type casts are redundant

Problem:    Some type casts are redundant.
Solution:   Remove the type casts. (closes #9643)
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index f5d93e6..099d9cf 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -1185,7 +1185,7 @@
 
     if (do_out)
     {
-	if (u_save((linenr_T)(line2), (linenr_T)(line2 + 1)) == FAIL)
+	if (u_save(line2, (linenr_T)(line2 + 1)) == FAIL)
 	{
 	    vim_free(cmd_buf);
 	    goto error;