net: phy: meson-gxl: Use the genphy_soft_reset callback

mainline inclusion
from mainline-4.20
commit f2f98c1d
category: bugfix
bugzilla: 6040
CVE: NA

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

Since the referenced commit, Ethernet fails to come up at boot on the
board meson-gxl-s905x-libretech-cc. Fix this by re-enabling the
genphy_soft_reset callback for the Amlogic Meson GXL PHY driver.

Fixes: 6e2d85ec ("net: phy: Stop with excessive soft reset")
Signed-off-by: Timotej Lazar <timotej.lazar@araneo.si>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>