tty: tty_baudrate: Remove unnecessary tab and spaces in comment sentence

Remove unnecessary tab and spaces in comment sentence, reported
by checkpatch.pl.
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Link: https://lore.kernel.org/r/1620811585-18582-2-git-send-email-tanxiaofei@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>