Simplify the use of CONFIG_DEVPORT by making the port_fops
so that it includes __maybe_unused.

This enabled the multiple #ifdef's used for this structure
to be removed and brings it in line with the use of CONFIG_DEVMEM

This change should introduce no functional changes.
Signed-off-by: NRob Ward <robert.ward114@googlemail.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>