dma-buf/sw_sync: Decrement refcount on error in sw_sync_ioctl_get_deadline()

Call dma_fence_put(fence) before returning an error if
dma_fence_to_sync_pt() fails.  Use an unwind ladder at the
end of the function to do the cleanup.

Fixes: 70e67aae ("dma-buf/sw_sync: Add fence deadline support")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/a010a1ac-107b-4fc0-a052-9fd3706ad690@stanley.mountain


Signed-off-by: Christian König <christian.koenig@amd.com>