Previously, fatfs was using NLS_DEFAULT if users didn't specify the
codepage or iocharset option.  This became cause of trouble (filename
access).

This patch removes the complicated default config in kernel.

Instead of it, by default, fatfs uses builtin nls ("default"), also reports
it and mounts as read-only.  This default will limit the access more or
less.  Note: If peoples want to write on this default, it still can switch
by remount.

Therefore, basically users will need to specify mount options always.
("codepage" for msdos, and "codepage" and "iocharset" for vfat) However, it
can be done simply by script or shell alias or something else in userland.

Thanks to Andries Brouwer for your many advice.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>