usbnet: smsc95xx: disable carrier check while suspending

[ Upstream commit 7b900ead6cc66b2ee873cb042dfba169aa68b56c ]

We need to make sure, that the carrier check polling is disabled
while suspending. Otherwise we can end up with usbnet_read_cmd()
being issued when only usbnet_read_cmd_nopm() is allowed. If this
happens, read operations lock up.

Fixes: d69d1694 ("usbnet: smsc95xx: fix link detection for disabled autonegotiation")
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Raghuram Chary J <RaghuramChary.Jallipalli@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>