tap: make struct tap_fops static

The structure tap_fops is local to the source and does not need to
be in global scope, so make it static.

Cleans up sparse warning:
symbol 'tap_fops' was not declared. Should it be static?
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/tap.c

@@ -1127,7 +1127,7 @@ static long tap_compat_ioctl(struct file *file, unsigned int cmd,
 }
 #endif
 
-const struct file_operations tap_fops = {
+static const struct file_operations tap_fops = {
 	.owner		= THIS_MODULE,
 	.open		= tap_open,
 	.release	= tap_release,