scsi: hpsa: free irq on q indexed by h->intr_mode and not i

Use correct index on q, use h->intr_mode instead of i. Issue detected
using static analysis with cppcheck

Fixes: bc2bb154 ("scsi: hpsa: use pci_alloc_irq_vectors and automatic irq affinity")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>