scsi: pm8001: Introduce ccb alloc/free helpers

scsi: pm8001: Introduce ccb alloc/free helpers

Introduce the pm8001_ccb_alloc() and pm8001_ccb_free() helpers to replace
the typical code patterns:

	res = pm8001_tag_alloc(pm8001_ha, &ccb_tag);
	if (res)
		...
	ccb = &pm8001_ha->ccb_info[ccb_tag];
	ccb->device = pm8001_ha_dev;
	ccb->ccb_tag = ccb_tag;
	ccb->task = task;
	ccb->n_elem = 0;

and

	ccb->task = NULL;
	ccb->ccb_tag = PM8001_INVALID_TAG;
	pm8001_tag_free(pm8001_ha, tag);

With the simpler function calls:

	ccb = pm8001_ccb_alloc(pm8001_ha, pm8001_ha_dev, task);
	if (!ccb)
		...

and

	pm8001_ccb_free(pm8001_ha, ccb);

The pm8001_ccb_alloc() helper ensures that all fields of the ccb info
structure for the newly allocated tag are all initialized, except the
buf_prd field. The pm8001_ccb_free() helper clears the initialized fields
and the ccb tag to ensure that iteration over the adapter ccb_info array
detects ccbs that are in use.

All call site of the pm8001_tag_alloc() function that use a ccb info
associated with an allocated tag are converted to use the new helpers.

Link: https://lore.kernel.org/r/20220220031810.738362-27-damien.lemoal@opensource.wdc.com
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>