drm: fix issue with contexts running out of RAM

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/drm_context.c b/drivers/char/drm/drm_context.c
index bdd168d..7a7bcef 100644
--- a/drivers/char/drm/drm_context.c
+++ b/drivers/char/drm/drm_context.c
@@ -432,6 +432,10 @@
 
 	if (ctx.handle != DRM_KERNEL_CONTEXT) {
 		if (dev->driver->context_ctor)
+			if (dev->driver->context_ctor(dev, ctx.handle)) {
+				DRM_DEBUG("Running out of ctxs or memory.\n");
+				return -ENOMEM;
+			}
 			dev->driver->context_ctor(dev, ctx.handle);
 	}