net: phy: resume phydev when going to RESUMING

With commit be9dad1f ("net: phy: suspend phydev when going
to HALTED"), an unused PHY device will be put in a low-power mode
using BMCR_PDOWN. Some Ethernet drivers might be calling phy_start()
and phy_stop() from ndo_open and ndo_close() respectively, while
calling phy_connect() and phy_disconnect() from probe and remove.
In such a case, the PHY will be powered down during the phy_stop()
call, but will fail to be powered up in phy_start().
This patch fixes this scenario.

Signed-off-by: Jiancheng Xue <xuejiancheng@huawei.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>