r8152 may fail to establish network connection after resume from system
suspend.

If the USB port connects to r8152 lost its power during system suspend,
the MAC address was written before is lost. The reason is that The MAC
address doesn't get written again in its reset_resume callback.

So let's set MAC address again in reset_resume callback. Also remove
unnecessary lock as no other locking attempt will happen during
reset_resume.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>