[S390] tape: duplicate sysfs filename when setting tape device online

When a tape device is set online, offline and online again, the following
error message is printed on the console: "sysfs: duplicate filename
'non-rewinding' can not be created". The reason is that when setting a
device online, the tape driver creates a sysfs symlink from the tape device
to the tape class device. Unfortunately the symlink is not removed
correctly, when the device is set offline. Instead of passing the
tape device object to sysfs_remove_link, the class device object is used.
This patch fixes this problem and uses the correct tape device object now.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>