drivers: char: mem: Simplify DEVPORT configuration

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: Rob Ward <robert.ward114@googlemail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/mem.c

@@ -542,7 +542,6 @@ static ssize_t write_kmem(struct file *file, const char __user *buf,
 	return virtr + wrote ? : err;
 }
 
-#ifdef CONFIG_DEVPORT
 static ssize_t read_port(struct file *file, char __user *buf,
 			 size_t count, loff_t *ppos)
 {
@@ -583,7 +582,6 @@ static ssize_t write_port(struct file *file, const char __user *buf,
 	*ppos = i;
 	return tmp-buf;
 }
-#endif
 
 static ssize_t read_null(struct file *file, char __user *buf,
 			 size_t count, loff_t *ppos)
@@ -738,14 +736,12 @@ static const struct file_operations null_fops = {
 	.splice_write	= splice_write_null,
 };
 
-#ifdef CONFIG_DEVPORT
-static const struct file_operations port_fops = {
+static const struct file_operations __maybe_unused port_fops = {
 	.llseek		= memory_lseek,
 	.read		= read_port,
 	.write		= write_port,
 	.open		= open_port,
 };
-#endif
 
 static const struct file_operations zero_fops = {
 	.llseek		= zero_lseek,