When the vivid module used to test buffer importing is not loaded, the
test correctly bails out, but during the clean up procedure tries to
access the video_ field, which, if not correctly initialized to
nullptr contains random values and accessing it causes a segfault.
Fix this by initializing video_ field to nullptr to make sure it is
properly handled in cleanup().
Fixes: e1a5873701 ("test: camera: Add buffer import and mapping test")
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
0f2e8cac8d