scsi: isci: Return result of sas_register_ha()

To properly manage possible failure of sas_register_ha() in
isci_register_sas_ha(), return its result instead of zero

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Link: https://lore.kernel.org/r/20230813202336.240874-1-artem.chernyshev@red-soft.ru
Reviewed-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>