dma-buf/dma-fence: Extract __dma_fence_is_later()

dma-buf/dma-fence: Extract __dma_fence_is_later()

commit 8111477663813caa1a4469cfe6afaae36cd04513 upstream.

Often we have the task of comparing two seqno known to be on the same
context, so provide a common __dma_fence_is_later().

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170629125930.821-1-chris@chris-wilson.co.uk
[renamed to __fence_is_later() - gregkh]
Cc: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>