tty/ldsem: Fix syntax errors in comments

Delete the redundant word 'are'.

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20211208142036.7956-1-wangxiang@cdjrlc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>