patch 8.1.1393: unnecessary type casts

Problem:    Unnecessary type casts.
Solution:   Remove type casts from alloc() and lalloc() calls. (Mike Williams)

src/ex_cmds.c

@@ -2746,7 +2746,7 @@ barline_parse(vir_T *virp, char_u *text, garray_T *values)
 		 */
 		++p;
 		len = getdigits(&p);
-		buf = alloc((int)(len + 1));
+		buf = alloc(len + 1);
 		if (buf == NULL)
 		    return TRUE;
 		p = buf;