drm/i915: Wrap vma->pin_count accessors with small inline helpers

In the next few patches, the VMA pinning API is overhauled and to reduce
the churn we pull out the update to the accessors into a prep patch.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470324762-2545-14-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index ef12ecd..7be4258 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -49,7 +49,7 @@
 static bool
 mark_free(struct i915_vma *vma, struct list_head *unwind)
 {
-	if (vma->pin_count)
+	if (i915_vma_is_pinned(vma))
 		return false;
 
 	if (WARN_ON(!list_empty(&vma->exec_list)))
@@ -183,7 +183,7 @@
 	 */
 	list_for_each_entry_safe(vma, next, &eviction_list, exec_list) {
 		if (drm_mm_scan_remove_block(&vma->node))
-			vma->pin_count++;
+			__i915_vma_pin(vma);
 		else
 			list_del_init(&vma->exec_list);
 	}
@@ -195,7 +195,7 @@
 				       exec_list);
 
 		list_del_init(&vma->exec_list);
-		vma->pin_count--;
+		__i915_vma_unpin(vma);
 		if (ret == 0)
 			ret = i915_vma_unbind(vma);
 	}
@@ -220,8 +220,8 @@
 
 		vma = container_of(node, typeof(*vma), node);
 
-		if (vma->pin_count) {
-			if (!vma->exec_entry || (vma->pin_count > 1))
+		if (i915_vma_is_pinned(vma)) {
+			if (!vma->exec_entry || i915_vma_pin_count(vma) > 1)
 				/* Object is pinned for some other use */
 				return -EBUSY;
 
@@ -281,7 +281,7 @@
 	}
 
 	list_for_each_entry_safe(vma, next, &vm->inactive_list, vm_link)
-		if (vma->pin_count == 0)
+		if (!i915_vma_is_pinned(vma))
 			WARN_ON(i915_vma_unbind(vma));
 
 	return 0;