scsi: isci: Remove a declaration

There is no function with the name isci_queuecommand(). Hence remove the
declaration for isci_queuecommand().

Link: https://lore.kernel.org/r/20211007204618.2196847-12-bvanassche@acm.org


Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>