patch 8.1.1386: unessesary type casts for lalloc()

Problem:    Unessesary type casts for lalloc().
Solution:   Remove type casts.  Change lalloc(size, TRUE) to alloc(size).
diff --git a/src/winclip.c b/src/winclip.c
index feef18d..f6f24d1 100644
--- a/src/winclip.c
+++ b/src/winclip.c
@@ -244,7 +244,7 @@
     char_u	*retp;
 
     /* Avoid allocating zero bytes, it generates an error message. */
-    ret = lalloc((long_u)(str_len == 0 ? 1 : str_len), TRUE);
+    ret = alloc(str_len == 0 ? 1 : str_len);
     if (ret != NULL)
     {
 	retp = ret;