scsi: target: tcmu: Fix boolreturn.cocci warnings

drivers/target/target_core_user.c:1424:9-10: WARNING: return of 0/1 in function 'tcmu_handle_completions' with return type bool

 Return statements in functions returning bool should use
 true/false instead of 1/0.

Generated by: scripts/coccinelle/misc/boolreturn.cocci

Link: https://lore.kernel.org/r/20210515230358.GA97544@60d1edce16e0
Fixes: 9814b55c

 ("scsi: target: tcmu: Return from tcmu_handle_completions() if cmd_id not found")
CC: Bodo Stroesser <bostroesser@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>