vfat: change the default from shortname=lower to shortname=mixed

Because, with "shortname=lower", copying one FAT filesystem tree to
another FAT filesystem tree using Linux results in semantically
different filesystems. (E.g.: Filenames which were once "all
uppercase" are now "all lowercase").

So, this changes the default of "shortname=lower" to "shortname=mixed".

Signed-off-by: Paul Wise <pabs3@bonedaddy.net>
[change fat_show_options()]
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt
index b58b84b..eed520f 100644
--- a/Documentation/filesystems/vfat.txt
+++ b/Documentation/filesystems/vfat.txt
@@ -102,7 +102,7 @@
 		 winnt: emulate the Windows NT rule for display/create.
 		 mixed: emulate the Windows NT rule for display,
 			emulate the Windows 95 rule for create.
-		 Default setting is `lower'.
+		 Default setting is `mixed'.
 
 tz=UTC        -- Interpret timestamps as UTC rather than local time.
                  This option disables the conversion of timestamps