net: phy: call state machine synchronously in phy_stop

mainline inclusion
from mainline-v4.20-rc1
commit e8cfd9d6
category: bugfix
bugzilla: NA
CVE: NA

----------------------------------------------------

phy_stop() may be called e.g. when suspending, therefore all needed
actions should be performed synchronously. Therefore add a synchronous
call to the state machine.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Weiwei Deng <dengweiwei@huawei.com>
Reviewed-by: Zhaohui Zhong <zhongzhaohui@huawei.com>
Reviewed-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: You Shengzui <youshengzui@huawei.com>
Reviewed-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>