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/fileio.c b/src/fileio.c
index 4182d56..96207ab 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -89,7 +89,7 @@
     int		bw_restlen;	/* nr of bytes in bw_rest[] */
     int		bw_first;	/* first write call */
     char_u	*bw_conv_buf;	/* buffer for writing converted chars */
-    int		bw_conv_buflen; /* size of bw_conv_buf */
+    size_t	bw_conv_buflen; /* size of bw_conv_buf */
     int		bw_conv_error;	/* set for conversion error */
     linenr_T	bw_conv_error_lnum;  /* first line with error or zero */
     linenr_T	bw_start_lnum;  /* line number at start of buffer */
@@ -1189,7 +1189,7 @@
 	    {
 		for ( ; size >= 10; size = (long)((long_u)size >> 1))
 		{
-		    if ((new_buffer = lalloc((long_u)(size + linerest + 1),
+		    if ((new_buffer = lalloc(size + linerest + 1,
 							      FALSE)) != NULL)
 			break;
 		}
@@ -4168,8 +4168,7 @@
 		write_info.bw_conv_buflen = bufsize * 2;
 	    else /* FIO_UCS4 */
 		write_info.bw_conv_buflen = bufsize * 4;
-	    write_info.bw_conv_buf
-			   = lalloc((long_u)write_info.bw_conv_buflen, TRUE);
+	    write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
 	    if (write_info.bw_conv_buf == NULL)
 		end = 0;
 	}
@@ -4180,8 +4179,7 @@
     {
 	/* Convert UTF-8 -> UCS-2 and UCS-2 -> DBCS.  Worst-case * 4: */
 	write_info.bw_conv_buflen = bufsize * 4;
-	write_info.bw_conv_buf
-			    = lalloc((long_u)write_info.bw_conv_buflen, TRUE);
+	write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
 	if (write_info.bw_conv_buf == NULL)
 	    end = 0;
     }
@@ -4191,8 +4189,7 @@
     if (converted && wb_flags == 0 && (wb_flags = get_mac_fio_flags(fenc)) != 0)
     {
 	write_info.bw_conv_buflen = bufsize * 3;
-	write_info.bw_conv_buf
-			    = lalloc((long_u)write_info.bw_conv_buflen, TRUE);
+	write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
 	if (write_info.bw_conv_buf == NULL)
 	    end = 0;
     }
@@ -4212,8 +4209,7 @@
 	{
 	    /* We're going to use iconv(), allocate a buffer to convert in. */
 	    write_info.bw_conv_buflen = bufsize * ICONV_MULT;
-	    write_info.bw_conv_buf
-			   = lalloc((long_u)write_info.bw_conv_buflen, TRUE);
+	    write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
 	    if (write_info.bw_conv_buf == NULL)
 		end = 0;
 	    write_info.bw_first = TRUE;