myri10ge: fix sleeping with bh disabled

[Stanislaw Gruszka <sgruszka@redhat.com>]

napi_disable() can not be called with bh disabled, move locking just
around myri10ge_ss_lock_napi() .

Patches fixes following bug:

[  114.278378] BUG: sleeping function called from invalid context at net/core/dev.c:4383 
<snip>
[  114.313712] Call Trace: 
[  114.314943]  [<ffffffff817010ce>] dump_stack+0x19/0x1b 
[  114.317673]  [<ffffffff810ce7f3>] __might_sleep+0x173/0x230 
[  114.320566]  [<ffffffff815b3117>] napi_disable+0x27/0x90 
[  114.323254]  [<ffffffffa01e437f>] myri10ge_close+0xbf/0x3f0 [myri10ge] 

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 270c9ee..6d1a956 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -2668,9 +2668,9 @@ static int myri10ge_close(struct net_device *dev)
 
 	del_timer_sync(&mgp->watchdog_timer);
 	mgp->running = MYRI10GE_ETH_STOPPING;
-	local_bh_disable(); /* myri10ge_ss_lock_napi needs bh disabled */
 	for (i = 0; i < mgp->num_slices; i++) {
 		napi_disable(&mgp->ss[i].napi);
+		local_bh_disable(); /* myri10ge_ss_lock_napi needs this */
 		/* Lock the slice to prevent the busy_poll handler from
 		 * accessing it.  Later when we bring the NIC up, myri10ge_open
 		 * resets the slice including this lock.
@@ -2679,8 +2679,8 @@ static int myri10ge_close(struct net_device *dev)
 			pr_info("Slice %d locked\n", i);
 			mdelay(1);
 		}
+		local_bh_enable();
 	}
-	local_bh_enable();
 	netif_carrier_off(dev);
 
 	netif_tx_stop_all_queues(dev);