patch 8.1.1393: unnecessary type casts

Problem:    Unnecessary type casts.
Solution:   Remove type casts from alloc() and lalloc() calls. (Mike Williams)
diff --git a/src/fileio.c b/src/fileio.c
index 96207ab..ee8c14d 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -7190,7 +7190,7 @@
     ga_init2(gap, (int)sizeof(char *), 20);
 
 #ifdef MSWIN
-    buf = alloc((int)MAXPATHL);
+    buf = alloc(MAXPATHL);
     if (buf == NULL)
 	return FAIL;
     STRNCPY(buf, path, MAXPATHL-5);