[BNX2]: Add link-down workaround on 5706 serdes.

In some blade systems using the 5706 serdes, the hardware sometimes
does not properly generate link down interrupts.  We add a workaround
in the driver's timer to force a link-down when some PHY registers
report loss of SYNC.

The parallel detect logic is cleaned up slightly to better integrate
the workaround.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bnx2.h b/drivers/net/bnx2.h
index c1ab30b..31a030a 100644
--- a/drivers/net/bnx2.h
+++ b/drivers/net/bnx2.h
@@ -6344,6 +6344,15 @@
 #define MII_BNX2_DSP_RW_PORT			0x15
 #define MII_BNX2_DSP_ADDRESS			0x17
 #define MII_BNX2_DSP_EXPAND_REG			 0x0f00
+#define MII_EXPAND_REG1				  (MII_BNX2_DSP_EXPAND_REG | 1)
+#define MII_EXPAND_REG1_RUDI_C			   0x20
+#define MII_EXPAND_SERDES_CTL			  (MII_BNX2_DSP_EXPAND_REG | 2)
+
+#define MII_BNX2_MISC_SHADOW			0x1c
+#define MISC_SHDW_AN_DBG			 0x6800
+#define MISC_SHDW_AN_DBG_NOSYNC			  0x0002
+#define MISC_SHDW_MODE_CTL			 0x7c00
+#define MISC_SHDW_MODE_CTL_SIG_DET		  0x0010
 
 #define MII_BNX2_BLK_ADDR			0x1f
 #define MII_BNX2_BLK_ADDR_IEEE0			 0x0000
@@ -6643,6 +6652,7 @@
 #define PHY_INT_MODE_LINK_READY_FLAG	0x200
 #define PHY_DIS_EARLY_DAC_FLAG		0x400
 #define REMOTE_PHY_CAP_FLAG		0x800
+#define PHY_FORCED_DOWN_FLAG		0x1000
 
 	u32			mii_bmcr;
 	u32			mii_bmsr;