libcamera: Fix maybe-uninitialized error

The gcc used in my current buildroot (Version 12.3) errors out with
-Wmaybe-uninitialized. Fix that.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
4 files changed