tty: moxa: drop ISA support

I doubt anyone actually uses this driver (unlike mxser.c and serial
moxa driven devices). Even less there is anyone with a moxa ISA card.
The newer mxser dropped the support for ISA in 2021. Let this moxa
follow now.

Good diet.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250317070046.24386-20-jirislaby@kernel.org


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