tg3: 5717: Allow serdes link via parallel detect

The 5717 serdes phy brings link up via parallel detection without any
additional help from the driver.  This patch changes the
tg3_setup_fiber_mii_phy() function to detect and allow the use of this
feature.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index d169337..2dcde13 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -4206,6 +4206,8 @@
 					current_duplex = DUPLEX_FULL;
 				else
 					current_duplex = DUPLEX_HALF;
+			} else if (!(tp->tg3_flags2 & TG3_FLG2_5780_CLASS)) {
+				/* Link is up via parallel detect */
 			} else {
 				current_link_up = 0;
 			}
@@ -8531,8 +8533,10 @@
 				}
 				tg3_setup_phy(tp, 0);
 			}
-		} else if (tp->tg3_flags2 & TG3_FLG2_MII_SERDES)
+		} else if ((tp->tg3_flags2 & TG3_FLG2_MII_SERDES) &&
+			   !(tp->tg3_flags2 & TG3_FLG2_5780_CLASS)) {
 			tg3_serdes_parallel_detect(tp);
+		}
 
 		tp->timer_counter = tp->timer_multiplier;
 	}