tty: jsm: remove unused struct jsm_board members

tty: jsm: remove unused struct jsm_board members

clang-struct [1] found jsm_board::type and ::jsm_board_entry unused.

::jsm_board_entry is unused since 614a7d6a76b7 ("fix up newly added jsm driver")
::type was never used as far as I can tell. Even when the driver was
introduced in the pre-git era.

Remove them both.

[1] https://github.com/jirislaby/clang-struct

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20231121103626.17772-5-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>