fs: fat: assign rootdir sector when accessing root directory

This fixes problems accessing drives formated under
Windows as FAT16.

Signed-off-by: Thomas RIENOESSL <thomas.rienoessl@bachmann.info>
[trini: Rebase on top of f528c140c801]
Signed-off-by: Tom Rini <trini@konsulko.com>

fs/fat/fat.c

@@ -725,7 +725,10 @@ static void *next_cluster(fat_itr *itr)
 	if (itr->last_cluster)
 		return NULL;
 
-	sect = clust_to_sect(itr->fsdata, itr->next_clust);
+	if (itr->fsdata->fatsize != 32 && itr->is_root)
+		sect = mydata->rootdir_sect;
+	else
+		sect = clust_to_sect(itr->fsdata, itr->next_clust);
 
 	debug("FAT read(sect=%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
 	      sect, itr->fsdata->clust_size, DIRENTSPERBLOCK);