tty: serial: altera_jtaguart: remove struct altera_jtaguart

It contains only struct uart_port, so no need for another structure.
Remove it and convert the rest to use struct uart_port directly.

Cc: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reviewed-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20221115071724.5185-4-jirislaby@kernel.org


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