Only register the braille driver VT and keyboard notifiers when the
braille console is used.  Avoids eating insert or backspace keys.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11242

Signed-off-by: Pascal Terjan <pterjan@mandriva.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>