net: phy: smsc: bail out in lan87xx_read_status if genphy_read_status fails

[ Upstream commit c22c3bbf ]

If genphy_read_status fails then further access to the PHY may result
in unpredictable behavior. To prevent this bail out immediately if
genphy_read_status fails.

Fixes: 4223dbff

 ("net: phy: smsc: Re-enable EDPD mode for LAN87xx")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/026aa4f2-36f5-1c10-ab9f-cdb17dda6ac4@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>