gpu: host1x: Plug potential memory leak

The memory allocated for a DMA fence could be leaked if the code failed
to allocate the waiter object. Make sure to release the fence allocation
on failure.

Reported-by: kernel test robot <[e-mail]>
Reported-by: Dan Carpenter <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

drivers/gpu/host1x/fence.c

···
 		return ERR_PTR(-ENOMEM);
 
 	fence->waiter = kzalloc(sizeof(*fence->waiter), GFP_KERNEL);
-	if (!fence->waiter)
+	if (!fence->waiter) {
+		kfree(fence);
 		return ERR_PTR(-ENOMEM);
+	}
 
 	fence->sp = sp;
 	fence->threshold = threshold;