mxser: remove MOXA_ASPP_MON and friends

mxser: remove MOXA_ASPP_MON and friends

1) MOXA_ASPP_MON_EXT is broken at least since commit ecbbfd44a08f (TTY:
   move tty buffers to tty_port) in 2012.
2) The ioctl definitions were never exposed to userspace, so noone should
   actually be reliably using them.
3) They're not even mentioned in any of the mxser utilities.

So remove all these mxser-special ioctls: MOXA_ASPP_MON,
MOXA_ASPP_MON_EXT, and MOXA_SDS_RSTICOUNTER.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210618061516.662-25-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>