scsi: hpsa: Fix allocation size for Scsi_Host private data

struct Scsi_Host private data contains pointer to struct ctlr_info.

Restore allocation of only 8 bytes to store pointer in struct Scsi_Host
private data area.

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

Fixes: bbbd2549

 ("scsi: hpsa: Fix allocation size for scsi_host_alloc()")
Signed-off-by: Yuri Karpov <YKarpov@ispras.ru>
Link: https://lore.kernel.org/r/20240312170447.743709-1-YKarpov@ispras.ru
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>