drm/mm: fix logic for selection of best fit block

This is from bug 25728.

[airlied: I'm just forwarding the patch for review, Thomas, ickle?]
Acked-by: NJerome Glisse <jglisse@redhat.com>
Acked-by: NThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_mm.c

@@ -358,7 +358,7 @@ struct drm_mm_node *drm_mm_search_free(const struct drm_mm *mm,
 		if (entry->size >= size + wasted) {
 			if (!best_match)
 				return entry;
-			if (size < best_size) {
+			if (entry->size < best_size) {
 				best = entry;
 				best_size = entry->size;
 			}
@@ -408,7 +408,7 @@ struct drm_mm_node *drm_mm_search_free_in_range(const struct drm_mm *mm,
 		if (entry->size >= size + wasted) {
 			if (!best_match)
 				return entry;
-			if (size < best_size) {
+			if (entry->size < best_size) {
 				best = entry;
 				best_size = entry->size;
 			}