scsi: pm80xx: Set stopped phy's linkrate to Disabled

Negotiated link rate needs to be updated to 'Disabled' when phy is stopped.

Link: https://lore.kernel.org/r/20220708205026.969161-1-changyuanl@google.com


Reviewed-by: Igor Pylypiv <ipylypiv@google.com>
Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>