MAINTAINERS: Update TTY layer for lists and recently added files

Add mailing lists for linux-serial and lkml for the TTY layer. And let's
list the recently added files. This makes it easier for get_maintainer.pl
to include linux-serial for patches.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20230721072334.59272-1-tony@atomide.com


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