drm: proper fix for drm_context

Bad patch in last version
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/char/drm/drm_context.c

@@ -432,11 +432,10 @@ int drm_addctx(struct inode *inode, struct file *filp,
 
 	if (ctx.handle != DRM_KERNEL_CONTEXT) {
 		if (dev->driver->context_ctor)
-			if (dev->driver->context_ctor(dev, ctx.handle)) {
+			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);
 	}
 
 	ctx_entry = drm_alloc(sizeof(*ctx_entry), DRM_MEM_CTXLIST);