drm/i915: Remove unused "valid" parameter from pte_encode

We never used any invalid ptes, those were put in place for
a possibility of doing gpu faults. However our batchbuffers are not
restricted in length, so everything needs to be pointing to something
and thus out-of-bounds is pointing to scratch.

Remove the valid flag as it is always true.

v2: Expand commit msg, patch reorder (Mika)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1476360162-24062-1-git-send-email-michal.winiarski@intel.com
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index cbda305..fe92e28 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -919,8 +919,7 @@
 	if (node.allocated) {
 		wmb();
 		ggtt->base.clear_range(&ggtt->base,
-				       node.start, node.size,
-				       true);
+				       node.start, node.size);
 		i915_gem_object_unpin_pages(obj);
 		remove_mappable_node(&node);
 	} else {
@@ -1228,8 +1227,7 @@
 	if (node.allocated) {
 		wmb();
 		ggtt->base.clear_range(&ggtt->base,
-				       node.start, node.size,
-				       true);
+				       node.start, node.size);
 		i915_gem_object_unpin_pages(obj);
 		remove_mappable_node(&node);
 	} else {