net: phy: broadcom: Only advertise EEE for supported modes

commit c056d480b40a68f2520ccc156c7fae672d69d57d upstream

We should not be advertising EEE for modes that we do not support,
correct that oversight by looking at the PHY device supported linkmodes.

Fixes: 99cec8a4 ("net: phy: broadcom: Allow enabling or disabling of EEE")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>