dma-buf: fix resource leak on -ENOTTY error return path

The -ENOTTY error return path does not free the allocated
kdata as it returns directly. Fix this by returning via the
error handling label err.

Addresses-Coverity: ("Resource leak")
Fixes: c02a81fb ("dma-buf: Add dma-buf heaps framework")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191216161059.269492-1-colin.king@canonical.com

drivers/dma-buf/dma-heap.c

@@ -157,7 +157,8 @@ static long dma_heap_ioctl(struct file *file, unsigned int ucmd,
 		ret = dma_heap_ioctl_allocate(file, kdata);
 		break;
 	default:
-		return -ENOTTY;
+		ret = -ENOTTY;
+		goto err;
 	}
 
 	if (copy_to_user((void __user *)arg, kdata, out_size) != 0)