sky2: receive FIFO checking

A driver writer from another operating system hinted that
the versions of Yukon 2 chip with rambuffer (EC and XL) have
a hardware bug that if the FIFO ever gets completely full it
will hang. Sounds like a classic ring full vs ring empty wrap around
bug.

As a workaround, use the existing watchdog timer to check for
ring full lockup.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/sky2.h b/drivers/net/sky2.h
index a05b30b..69cd984 100644
--- a/drivers/net/sky2.h
+++ b/drivers/net/sky2.h
@@ -2027,6 +2027,14 @@
 	u16		     rx_tag;
 	struct vlan_group    *vlgrp;
 #endif
+	struct {
+		unsigned long last;
+		u32	mac_rp;
+		u8	mac_lev;
+		u8	fifo_rp;
+		u8	fifo_lev;
+	} check;
+
 
 	dma_addr_t	     rx_le_map;
 	dma_addr_t	     tx_le_map;
@@ -2064,7 +2072,6 @@
 	u8		     chip_rev;
 	u8		     pmd_type;
 	u8		     ports;
-	u8		     active;
 
 	struct sky2_status_le *st_le;
 	u32		     st_idx;