scsi: pm8001: Provide descriptions for the many undocumented 'attr's

scsi: pm8001: Provide descriptions for the many undocumented 'attr's

... even if they are completely unused.

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/pm8001/pm8001_ctl.c:56: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_mpi_interface_rev_show'
 drivers/scsi/pm8001/pm8001_ctl.c:81: warning: Function parameter or member 'attr' not described in 'controller_fatal_error_show'
 drivers/scsi/pm8001/pm8001_ctl.c:100: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_fw_version_show'
 drivers/scsi/pm8001/pm8001_ctl.c:130: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_ila_version_show'
 drivers/scsi/pm8001/pm8001_ctl.c:155: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_inactive_fw_version_show'
 drivers/scsi/pm8001/pm8001_ctl.c:181: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_max_out_io_show'
 drivers/scsi/pm8001/pm8001_ctl.c:204: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_max_devices_show'
 drivers/scsi/pm8001/pm8001_ctl.c:230: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_max_sg_list_show'
 drivers/scsi/pm8001/pm8001_ctl.c:274: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_sas_spec_support_show'
 drivers/scsi/pm8001/pm8001_ctl.c:303: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_host_sas_address_show'
 drivers/scsi/pm8001/pm8001_ctl.c:322: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_logging_level_show'
 drivers/scsi/pm8001/pm8001_ctl.c:355: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_aap_log_show'
 drivers/scsi/pm8001/pm8001_ctl.c:390: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_ib_queue_log_show'
 drivers/scsi/pm8001/pm8001_ctl.c:423: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_ob_queue_log_show'
 drivers/scsi/pm8001/pm8001_ctl.c:454: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_bios_version_show'
 drivers/scsi/pm8001/pm8001_ctl.c:492: warning: Function parameter or member 'attr' not described in 'event_log_size_show'
 drivers/scsi/pm8001/pm8001_ctl.c:510: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_iop_log_show'
 drivers/scsi/pm8001/pm8001_ctl.c:548: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_fatal_log_show'
 drivers/scsi/pm8001/pm8001_ctl.c:566: warning: Function parameter or member 'attr' not described in 'non_fatal_log_show'
 drivers/scsi/pm8001/pm8001_ctl.c:609: warning: Function parameter or member 'attr' not described in 'pm8001_ctl_gsm_log_show'

Link: https://lore.kernel.org/r/20200713080001.128044-11-lee.jones@linaro.org
Cc: Jack Wang <jinpu.wang@cloud.ionos.com>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>