scsi: qla2xxx: make msix_entries const

msix_entries and qla82xx_msix_entries arrays are never modified in
drivers/scsi/qla2xxx/qla_isr.c. Move their contents to read-only data.

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>