Avoid the PHY library call unnecessarily into the suspend/resume
functions by setting phydev->mac_managed_pm to true. The SYSTEMPORT
driver essentially does exactly what mdio_bus_phy_resume() does by
calling phy_resume().

Fixes: fba863b8 ("net: phy: make PHY PM ops a no-op if MAC driver manages PHY PM")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20221025234201.2549360-1-f.fainelli@gmail.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>