Add a forgotten kfree().

Fixes: dbec4c90 ("scsi: mpt3sas: lockless command submission")
Link: https://lore.kernel.org/r/20230207152159.18627-1-thenzl@redhat.comSigned-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>