alx: make sizes unsigned

The ring sizes should be unsigned, pointed out by Ben Hutchings.
Reported-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/atheros/alx/alx.h

@@ -85,16 +85,16 @@ struct alx_priv {
 	struct {
 		dma_addr_t dma;
 		void *virt;
-		int size;
+		unsigned int size;
 	} descmem;
 
 	/* protect int_mask updates */
 	spinlock_t irq_lock;
 	u32 int_mask;
 
-	int tx_ringsz;
-	int rx_ringsz;
-	int rxbuf_size;
+	unsigned int tx_ringsz;
+	unsigned int rx_ringsz;
+	unsigned int rxbuf_size;
 
 	struct napi_struct napi;
 	struct alx_tx_queue txq;