scsi: libsas: Add struct sas_tmf_task

scsi: libsas: Add struct sas_tmf_task

Some of the LLDDs which use libsas have their own definition of a struct
to hold TMF info, so add a common struct for libsas.

Also add an interim force phy id field for hisi_sas driver, which will be
removed once the STP "TMF" code is factored out.

Even though some LLDDs (pm8001) use a u32 for the tag, u16 will be adequate,
as that named driver only uses tags in range [0, 1024).

Link: https://lore.kernel.org/r/1645112566-115804-8-git-send-email-john.garry@huawei.com
Tested-by: Yihang Li <liyihang6@hisilicon.com>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>