s390/tape: Remove tape load display support

s390/tape: Remove tape load display support

The LOAD_DISPLAY (LDD) X'9F' is still accepted by the Virtual Tape
Server (VTS) but does not perform any action.

Remove all functions and definitions related to this command.

The tape_34xx_ioctl() function is also removed as it was mainly used to
handle additional ioctl functionality. LOAD_DISPLAY was the only left
case. All other ioctls are handled in tapechar_ioctl().

With LOAD_DISPLAY, the remaining definitions in asm/tape390.h are gone.
Delete the file.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>