net: phy: dp83tg720: wake up PHYs in managed mode

In case this PHY is bootstrapped for managed mode, we need to manually
wake it. Otherwise no link will be detected.

Cc: stable@vger.kernel.org
Fixes: cb80ee2f

 ("net: phy: Add support for the DP83TG720S Ethernet PHY")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20240614094516.1481231-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>