nfc: Fix portid type in urelease_work

portid is an unsigned integer. Fix urelease_work to
match all other portid user in the kernel.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 14a2d11..3763036 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -1584,7 +1584,7 @@
 
 struct urelease_work {
 	struct	work_struct w;
-	int	portid;
+	u32	portid;
 };
 
 static void nfc_urelease_event_work(struct work_struct *work)