net/macb: suppress compiler warnings

This patch fixes the following warnings:
drivers/net/ethernet/cadence/macb.c: In function ‘macb_handle_link_change’:
drivers/net/ethernet/cadence/macb.c:266: warning: comparison between signed and unsigned
drivers/net/ethernet/cadence/macb.c:267: warning: comparison between signed and unsigned
drivers/net/ethernet/cadence/macb.c:291: warning: comparison between signed and unsigned
drivers/net/ethernet/cadence/macb.c: In function ‘gem_update_stats’:
drivers/net/ethernet/cadence/macb.c:1908: warning: comparison between signed and unsigned
drivers/net/ethernet/cadence/macb.c: In function ‘gem_get_ethtool_strings’:
drivers/net/ethernet/cadence/macb.c:1988: warning: comparison between signed and unsigned

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index f245340..2aa102e 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -816,9 +816,9 @@
 
 	struct mii_bus		*mii_bus;
 	struct phy_device	*phy_dev;
-	unsigned int 		link;
-	unsigned int 		speed;
-	unsigned int 		duplex;
+	int 			link;
+	int 			speed;
+	int 			duplex;
 
 	u32			caps;
 	unsigned int		dma_burst_length;