tty: tty_ldisc: Remove the ret variable

The int variable ret does not receive the return value in this function.
It should be removed and returned 0 directly.

Signed-off-by: Li zeming <zeming@nfschina.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230222202303.3195-1-zeming@nfschina.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>