tty: tty_io: Remove the repeated word 'can'

Remove the repeated word 'can' following advice of checkpatch.pl

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-12-git-send-email-tanxiaofei@huawei.com


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