accessibility: speakup: unregister tty ldisc on later init failures

accessibility: speakup: unregister tty ldisc on later init failures

commit a76acbaec9b8fd74413646984d2e3626d0543e39 upstream.

The ldisc registration is intentionally non-fatal, since some synth
drivers do not use tty/ldisc.  However, once speakup_init() continues
past the registration point and later fails, the init unwind path should
mirror speakup_exit() and call spk_ttyio_unregister_ldisc().

Add the missing unregister call to the error path after synth_release(),
matching the normal module exit cleanup order.

Signed-off-by: Haoxiang Li <lihaoxiang@isrc.iscas.ac.cn>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Fixes: e23a9b439ce9 ("staging: speakup: safely register and unregister ldisc")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260531230804.254962-16-samuel.thibault@ens-lyon.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>