Allow the DmaBufAllocator used by the software ISP to use memfd() + /dev/udmabuf for the software ISP destination buffers. This is useful on Linux distributions where normal users are not allowed to access /dev/dma_heap/* while they are allowed to access /dev/udmabuf. Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org> # Lenovo-x13s Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>