nfc: nfcsim: constify drvdata (struct nfcsim)

nfcsim_abort_cmd() does not modify struct nfcsim, so local variable
can be a pointer to const.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/nfc/nfcsim.c

@@ -240,7 +240,7 @@ static int nfcsim_send(struct nfc_digital_dev *ddev, struct sk_buff *skb,
 
 static void nfcsim_abort_cmd(struct nfc_digital_dev *ddev)
 {
-	struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
+	const struct nfcsim *dev = nfc_digital_get_drvdata(ddev);
 
 	nfcsim_link_recv_cancel(dev->link_in);
 }