tty: Fix LED error return

3.4-rc introduced a regression when setting the LEDS. We do the right thing
but then return an error code.

Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=43144


Reported-by: Christian Casteyde
Signed-off-by: Alan Cox <alan@linux/intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>