libcamera: pipeline_handler: Make lock() and unlock() thread-safe

The PipelineHandler lock() and unlock() functions are documented as
thread-safe, but they're not. Fix them using a mutex.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
2 files changed