s390: tape_class.h: remove kobj_map.h inclusion

This include file is not needed for any driver to be referencing, so
remove it from the tape_class.h file.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>