It's UTF-8

Fix some comments to "UTF-8".

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index db0de5c..4095bc1 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -114,7 +114,7 @@
 }
 
 /*
- * Convert Unicode 16 to UTF8, translated Unicode, or ASCII.
+ * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
  * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
  * colon as an escape character since it is normally invalid on the vfat
  * filesystem. The following four characters are the hexadecimal digits