drm/i915: Move the eviction logic to its own file.

The eviction code is the gnarly underbelly of memory management, and is
clearer if kept separated from the normal domain management in GEM.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index da78f2c..384fd45 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -8,6 +8,7 @@
           i915_suspend.o \
 	  i915_gem.o \
 	  i915_gem_debug.o \
+	  i915_gem_evict.o \
 	  i915_gem_tiling.o \
 	  i915_trace_points.o \
 	  intel_display.o \