drm/i915: Generalise the clflush dma-worker

Extract the dma-fence worker used by clflush for wider use, as we
anticipate using workers coupled to dma-fences more frequently.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190821191606.17001-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 45add81..658b930 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -62,6 +62,7 @@
 	i915_memcpy.o \
 	i915_mm.o \
 	i915_sw_fence.o \
+	i915_sw_fence_work.o \
 	i915_syncmap.o \
 	i915_user_extensions.o