drivers/net/cxgb3: fix sparse warnings: fix signedness

Fix this sparse warning:
  drivers/net/cxgb3/ael1002.c:1010:60: warning: incorrect type in argument 4 (different signedness)

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Acked-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/cxgb3/ael1002.c b/drivers/net/cxgb3/ael1002.c
index 5c3c05d..e1b2249 100644
--- a/drivers/net/cxgb3/ael1002.c
+++ b/drivers/net/cxgb3/ael1002.c
@@ -1005,7 +1005,8 @@
 		{ 0, 0, 0, 0 }
 	};
 
-	int err, lasi_ctrl;
+	int err;
+	unsigned int lasi_ctrl;
 
 	err = mdio_read(phy, MDIO_DEV_PMA_PMD, LASI_CTRL, &lasi_ctrl);
 	if (err)