s390/tape: Remove 3590 Read Opposite error recovery

s390/tape: Remove 3590 Read Opposite error recovery

On old native type 3590 tape devices a Read Opposite error recovery
procedure on Error Recovery Action Code (ERA) 26 was issued if a Read
Forward command failed. This recovery procedure was implemented with the
Read Backward command. This is no longer supported.

Remove 3590 ERA 26 and Read Backward related recovery code.

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>