scsi: qla2xxx: Use get_unaligned_*() instead of open-coding these functions

This patch improves readability and does not change any functionality.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Cc: Quinn Tran <qutran@marvell.com>
Cc: Martin Wilck <mwilck@suse.com>
Cc: Daniel Wagner <dwagner@suse.de>
Cc: Roman Bolshakov <r.bolshakov@yadro.com>
Link: https://lore.kernel.org/r/20191219005050.40193-1-bvanassche@acm.org


Reviewed-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>