scsi: pm80xx: Restore support for expanders

scsi: pm80xx: Restore support for expanders

Commit 0f630c58e31a ("scsi: pm80xx: Do not use libsas port ID") broke
support for expanders. After the commit, devices behind an expander are
no longer detected.

Simply reverting the commit restores support for devices behind an
expander.

Instead of reverting the commit (and reintroducing a helper to get the
port), get the port directly from the lldd_port pointer in struct
asd_sas_port.

Fixes: 0f630c58e31a ("scsi: pm80xx: Do not use libsas port ID")
Suggested-by: Igor Pylypiv <ipylypiv@google.com>
Reviewed-by: Igor Pylypiv <ipylypiv@google.com>
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Link: https://lore.kernel.org/r/20250814173215.1765055-13-cassel@kernel.org
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>