drm/i915: Rename i915_gem_context_reference/unreference()

As these are wrappers around kref_get/kref_put() it is preferable to
follow the naming convention and use the same verb get/put in our
wrapper names for manipulating a reference to the context.

s/i915_gem_context_reference/i915_gem_context_get/
s/i915_gem_context_unreference/i915_gem_context_put/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-3-git-send-email-chris@chris-wilson.co.uk
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-2-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index b23d4cc..6282fca 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -980,7 +980,6 @@
 	if (ret)
 		goto unpin_map;
 
-	i915_gem_context_reference(ctx);
 	ce->lrc_vma = i915_gem_obj_to_ggtt(ce->state);
 	intel_lr_context_descriptor_update(ctx, engine);
 
@@ -992,6 +991,7 @@
 	if (i915.enable_guc_submission)
 		I915_WRITE(GEN8_GTCR, GEN8_GTCR_INVALIDATE);
 
+	i915_gem_context_get(ctx);
 	return 0;
 
 unpin_map:
@@ -1023,7 +1023,7 @@
 	ce->lrc_desc = 0;
 	ce->lrc_reg_state = NULL;
 
-	i915_gem_context_unreference(ctx);
+	i915_gem_context_put(ctx);
 }
 
 static int intel_logical_ring_workarounds_emit(struct drm_i915_gem_request *req)