BlackBerry: Fix the rotation of the viewfinder

This fixes the rotation of the viewfinder. We have to adjust the orientation
depending on the primary screen orientation. On a keyboard device, the viewfinder
would not rotate at all (same if auto orientation is turned off).

Task-number: QTBUG-37894
Change-Id: I2bf955fb3303ed236d3234154ded94fe78607455
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>
Reviewed-by: Bernd Weimer <bweimer@blackberry.com>
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>