scsi: target: tcmu: Adjust parameter in call to tcmu_blocks_release()

scsi: target: tcmu: Adjust parameter in call to tcmu_blocks_release()

In commit f7c89771d07d ("scsi: target: tcmu: Replace radix_tree with
XArray") the meaning of last parameter of tcmu_blocks_release() was
changed.  So in the callers we should subtract 1 from the previous
parameter.

Unfortunately that change got lost at one of the two places where
tcmu_blocks_release() is called. That does not lead to any problems, but we
should adjust it anyway.

Link: https://lore.kernel.org/r/20210310184458.10741-1-bostroesser@gmail.com
Signed-off-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>