accel/ethosu: fix job completion fence cleanup

In the Linux kernel, the following vulnerability has been resolved: accel/ethosu: fix job completion fence cleanup ethosu_ioctl_submit_job() allocates done_fence before validating buffer handles. Errors after allocation call ethosu_job_err_cleanup(), which frees the job but leaks the uninitialized fence. A scheduler dependency error also lets ethosu_job_run() return before dma_fence_init(). Normal cleanup then passes a zeroed refcount to dma_fence_put(). Release done_fence in the common cleanup path and use dma_fence_was_initialized() to distinguish initialized fences from raw allocations. [robh: also fix goto]