drm: radeon: check kzalloc() result

If kzalloc() fails exit with -ENOMEM.

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r300.c b/drivers/gpu/drm/radeon/r300.c
index 0a1638c..19a7ef7 100644
--- a/drivers/gpu/drm/radeon/r300.c
+++ b/drivers/gpu/drm/radeon/r300.c
@@ -1177,6 +1177,8 @@
 	int r;
 
 	track = kzalloc(sizeof(*track), GFP_KERNEL);
+	if (track == NULL)
+		return -ENOMEM;
 	r100_cs_track_clear(p->rdev, track);
 	p->track = track;
 	do {