fat: reset VFAT short alias checksum on first match

The VFAT short alias checksum read from a long file name is only overwritten
when another long file name appears in a directory list. Until then it renders
short file names invisible that have the same checksum. Reset the checksum on
first match.
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NMartin Mueller <martin.mueller5@de.bosch.com>

fs/fat/fat.c

@@ -633,6 +633,7 @@ static dir_entry *get_dentfromdir (fsdata *mydata, int startsect,
 			}
 #ifdef CONFIG_SUPPORT_VFAT
 			if (dols && mkcksum(dentptr->name) == prevcksum) {
+				prevcksum = 0xffff;
 				dentptr++;
 				continue;
 			}
@@ -963,6 +964,7 @@ do_fat_read (const char *filename, void *buffer, unsigned long maxsize,
 #ifdef CONFIG_SUPPORT_VFAT
 			else if (dols == LS_ROOT &&
 				 mkcksum(dentptr->name) == prevcksum) {
+				prevcksum = 0xffff;
 				dentptr++;
 				continue;
 			}