netpoll: Fix carrier detection for drivers that are using phylib

Using early netconsole and gianfar driver this error pops up:

  netconsole: timeout waiting for carrier

It appears that net/core/netpoll.c:netpoll_setup() is using
cond_resched() in a loop waiting for a carrier.

The thing is that cond_resched() is a no-op when system_state !=
SYSTEM_RUNNING, and so drivers/net/phy/phy.c's state_queue is never
scheduled, therefore link detection doesn't work.

I belive that the main problem is in cond_resched()[1], but despite
how the cond_resched() story ends, it might be a good idea to call
msleep(1) instead of cond_resched(), as suggested by Andrew Morton.

[1] http://lkml.org/lkml/2009/7/7/463

Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

net/core/netpoll.c

@@ -740,7 +740,7 @@ int netpoll_setup(struct netpoll *np)
 				       np->name);
 				break;
 			}
-			cond_resched();
+			msleep(1);
 		}
 
 		/* If carrier appears to come up instantly, we don't