scsi: qla2xxx: Fix flash read for Qlogic ISPs

Use adapter specific callback to read flash instead of ISP adapter
specific.

Signed-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Link: https://lore.kernel.org/r/20190830222402.23688-3-hmadhani@marvell.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>