android: mm: Null check for CameraBufferManager

cros::CameraBufferManager can be nullptr if there is an error in
its creation. Place a null-check guard to check it.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/android/mm/cros_camera_buffer.cpp

@@ -60,6 +60,11 @@ CameraBuffer::Private::Private([[maybe_unused]] CameraBuffer *cameraBuffer,
 	  registered_(false)
 {
 	bufferManager_ = cros::CameraBufferManager::GetInstance();
+	if (!bufferManager_) {
+		LOG(HAL, Fatal)
+			<< "Failed to get cros CameraBufferManager instance";
+		return;
+	}
 
 	int ret = bufferManager_->Register(camera3Buffer);
 	if (ret) {