scsi: scsi_debug: Delete some bogus error checking

scsi: scsi_debug: Delete some bogus error checking

Smatch complains that "dentry" is never initialized.  These days everyone
initializes all their stack variables to zero so this means that it will
trigger a warning every time this function is run.

Really, debugfs functions are not supposed to be checked for errors in
normal code.  For example, if we updated this code to check the correct
variable then it would print a warning if CONFIG_DEBUGFS was disabled.  We
don't want that.  Just delete the check.

Fixes: f084fe52c640 ("scsi: scsi_debug: Add debugfs interface to fail target reset")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/c602c9ad-5e35-4e18-a47f-87ed956a9ec2@moroto.mountain
Reviewed-by: Wenchao Hao <haowenchao2@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>