r8152: remove a netif_carrier_off in rtl8152_open function

After commit 90186af4

 ("r8152: fix lockup when runtime PM is enabled"),
the autoresume wouldn't start the device before rtl8152_open() is finished.
Therefore, we don't have to reset the linking status before and after
autoresume. That is, one of netif_carrier_off() in rtl8152_open() could be
removed.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>