Add helper to check if fence is array.

v2: Comments from Chris Wilson
	- remove ternary if from ops comparison
	- add EXPORT_SYMBOL(fence_array_ops)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>